Merge branch 'issue1' into 'ssa'

Generalize RTL normalization checker

This MR generalizes the RTL normalization checker.

The entry point of the initial function is not necessarily reached after just a single goto.
On CFG where the entry point is a junction point, there will be a tunnel of 2 gotos from the entry point of the normalized function and the entry point of the initial function.

Closes #1

See merge request compcertssa/compcertssa!1

24 files changed, 11929 insertions, 43 deletions

diff --git a/.gitignore b/.gitignore
index e437c762..719507e5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -74,6 +74,12 @@
 .DS_Store
 # Test generated data
 /test/clightgen/*.v
+/test/picosat-965/picogcnf
+/test/picosat-965/picomcs
+/test/picosat-965/picomus
+/test/picosat-965/picosat
+/test/picosat-965/config.h
+/test/picosat-965/makefile
 # Coq caches
 .lia.cache
 .nia.cache
diff --git a/midend/CSSAgen.v b/midend/CSSAgen.v
index 968195c6..1e67c810 100644
--- a/midend/CSSAgen.v
+++ b/midend/CSSAgen.v
@@ -149,7 +149,7 @@ Qed.
 Definition add_parcopy (parcopy: CSSA.parcopy) (pc: node) : mon unit :=
   fun s =>
     match PTree.get pc (st_parcopycode s) with
-    | None => Error (Errors.msg "")
+    | None => Error (Errors.msg "CSSAgen - 1")
     | Some parcopies =>
       let new_parcb := parcopy :: parcopies
       in
@@ -188,7 +188,7 @@ Definition add_new_phi (dst': reg ) (args': list reg)
     (pc: node) :=
   fun s =>
   match PTree.get pc (st_phicode s) with
-    | None => Error (Errors.msg "")
+    | None => Error (Errors.msg "CSSAgen - 2")
     | Some phib' =>
         OK tt 
           (mkstate
diff --git a/midend/RTLnorm.v b/midend/RTLnorm.v
index a1b36d0f..0a026286 100644
--- a/midend/RTLnorm.v
+++ b/midend/RTLnorm.v
@@ -87,7 +87,7 @@ Definition add_nop (pc':node) : mon node :=
   fun s =>
     let pc_new := s.(st_nextnode) in
       if peq pc' s.(st_entry)
-      then Error (Errors.msg "")
+      then Error (Errors.msg "RTLnorm - 1")
       else OK pc_new
               (mkstate (Pos.succ pc_new) 
                        (st_entry s) 
@@ -126,7 +126,7 @@ Definition upd_pred (preds_pc : list node) (pc pcnew: node) : mon unit :=
                     OK tt (mkstate (st_nextnode s)
                                    (st_entry s)
                                    (PTree.set pred (ch_successors i pc pcnew) (st_code s))) 
-                  | None => Error (Errors.msg "")
+                  | None => Error (Errors.msg "RTLnorm - 2")
                 end) 
              preds_pc.
 
@@ -189,7 +189,7 @@ Definition upd_succ (pc: node) (newsucc:node) (k: nat): mon nat :=
                      (mkstate (st_nextnode s)
                               (st_entry s)
                               (PTree.set pc (ins_newsucc i newsucc k) s.(st_code)))
-      | None => Error (Errors.msg "")
+      | None => Error (Errors.msg "RTLnorm - 3")
     end.
 
 (** [modif_ksucc] changes the instruction at [pc] concerning its
@@ -200,7 +200,7 @@ Definition modif_ksucc (is_jp:node->bool) (pc: node) (succ:node) (k: nat) : mon
       match (st_code s) ! pc with
         | None 
         | Some (Ireturn _) 
-        | Some (Itailcall _ _ _) => (Error (Errors.msg ""))
+        | Some (Itailcall _ _ _) => (Error (Errors.msg "RTLnorm - 4"))
         | _ =>
           if is_jp succ
             then
@@ -361,9 +361,10 @@ Definition checker (c: code) (tc: code) : bool :=
   PTree.fold (fun res pc i => res && (check_pc c tc pc i)) c true. 
 
 Definition check_entry (f tf: function) : bool := 
-  match (fn_code tf) ! (fn_entrypoint tf) with 
-      | Some (Inop ts) => peq ts (fn_entrypoint f)
-      | _ => false
+  match (fn_code tf) ! (fn_entrypoint tf) with
+  | Some (Inop s) =>
+    (peq s (fn_entrypoint f)) || inop_tunel 3 (fn_code tf) (fn_entrypoint f) s
+  | _ => false
   end.
 
 Definition transl_function (f: RTL.function) : Errors.res RTL.function :=
@@ -387,9 +388,11 @@ Definition transl_function (f: RTL.function) : Errors.res RTL.function :=
                            f.(RTL.fn_stacksize)
                            s''.(st_code)
                            s''.(st_entry)) in 
-              if (checker (fn_code f) (fn_code tf) && check_entry f tf) then
-                Errors.OK tf
-              else Errors.Error (Errors.msg "")
+              if checker (fn_code f) (fn_code tf) then
+                if (check_entry f tf)
+                then Errors.OK tf
+                else Errors.Error (Errors.msg "RTLnorm - 5")
+              else Errors.Error (Errors.msg "RTLnorm - 6")
           end
       end
   end.
diff --git a/midend/RTLnormspec.v b/midend/RTLnormspec.v
index 3f975c4b..a04174f6 100644
--- a/midend/RTLnormspec.v
+++ b/midend/RTLnormspec.v
@@ -71,7 +71,55 @@ Proof.
   destruct i, i'; go. 
   simpl. intros ; boolInv; auto.
 Qed.
- 
+
+Lemma inop_tunel_reach_nops : forall code n s1 s2,
+    inop_tunel n code s1 s2 = true ->
+    (s2 = s1) \/ exists aux, reach_nops code s2 s1 aux.
+Proof.
+  unfold inop_tunel.
+  induction n; intros.
+  - rewrite orb_false_r in H.
+    destruct peq in H.
+    + subst; auto.
+    + inv H.
+  - fold inop_tunel in *.
+    destruct peq in H.
+    + subst. auto.
+    + rewrite orb_false_l in H.
+      flatten H; try congruence.
+      subst.
+      eapply IHn in H; eauto.
+      inv H.
+      * right.
+        exists nil.
+        econstructor; eauto.
+      * right.
+        destruct H0 as [aux Haux].
+        exists (n1::aux).
+        econstructor; eauto.
+Qed.
+
+Lemma check_entry_correct : forall f tf,
+    check_entry f tf = true ->
+    exists aux, reach_nops (fn_code tf) (fn_entrypoint tf) (fn_entrypoint f) aux.
+Proof.
+  unfold check_entry; intros.
+  flatten H. subst.
+  apply orb_true_iff in H. inv H.
+  - destruct peq.
+    + subst.
+      exists nil.
+      constructor; auto.
+    + inv H0.
+  - eapply inop_tunel_reach_nops in H0; eauto.
+    inv H0.
+    + exists nil.
+      constructor; auto.
+    + destruct H as [aux Haux].
+      exists (n::aux).
+      econstructor; eauto.
+Qed.
+
 Lemma check_mks_spec_correct: forall code tcode pc i ti,
   code ! pc = Some i ->
   tcode ! pc = Some ti ->
@@ -84,21 +132,8 @@ Proof.
   econstructor ; eauto.
   intros k succ succ' SUCC SUCC'.
   exploit ch_succ_same_length; eauto. intros LENGTH.
-  exploit @forall_list2_nth_error; eauto. simpl; intros.
-  destruct (peq succ succ') eqn: EQ ; subst.
-  + auto. 
-  + right.  
-    unfold inop_tunel in H.
-    flatten H; subst;
-    (repeat (match goal with 
-                | id : _ || _ = true |- _ => 
-                  eapply orb_prop in id; invh or
-              end); 
-      repeat (match goal with 
-                | id : _ = true |- _ => 
-                  apply proj_sumbool_true in id ; subst
-              end); go).
-    exists (n0::n1::nil); go.
+  exploit @forall_list2_nth_error; eauto.
+  eapply inop_tunel_reach_nops; eauto.
 Qed.
 
 Lemma checker_correct : forall code tcode pc i,
@@ -112,17 +147,16 @@ Proof.
   flatten CHECK; try congruence. boolInv.
   eapply check_mks_spec_correct ; eauto ; go.
 Qed.    
-    
+  
 Lemma transl_function_spec_ok : forall f tf, 
   transl_function f = Errors.OK tf -> 
   transl_function_spec f tf.
 Proof.
   unfold transl_function ; intros f tf TRANS. 
   flatten TRANS. boolInv. simpl in *.
-  eapply transl_function_spec_intro ; eauto. 
-  - intros. simpl in *.
-    eapply checker_correct; eauto.
-  - unfold check_entry in *. 
-    flatten H5; try congruence.
-    destruct peq; go. 
+  eapply check_entry_correct in Eq3; eauto.
+  destruct Eq3 as [aux Hentry]. 
+  eapply transl_function_spec_intro; eauto.
+  intros.
+  eapply checker_correct; eauto.
 Qed.
diff --git a/midend/SSAvalid.v b/midend/SSAvalid.v
index d334cb24..2bc6d470 100644
--- a/midend/SSAvalid.v
+++ b/midend/SSAvalid.v
@@ -239,7 +239,7 @@ Definition update_ctx (size: nat) (preds: PTree.t (list positive))
                     OK (G,
                         PTree.set pc (Inop l) new_code,
                         juncpoints)
-                  else Error (msg "SSAvalid 1") 
+                  else Error (msg "SSAvalid - 1") 
               end
             else
               OK (PTree.set l g G, 
@@ -264,7 +264,7 @@ Definition update_ctx (size: nat) (preds: PTree.t (list positive))
               OK (PTree.set succ (PTree.set dest i g) G,
                   PTree.set pc (Iop op (map use args) dest' succ) new_code,
                   juncpoints)
-            else Error (msg "SSAvalid 2")
+            else Error (msg "SSAvalid - 2")
           | RTL.Iload chunk addr args dest succ => 
             do i <- get_option (def ! pc) "" ; 
             let dest' := Bij.pamr size (dest,i) in
@@ -272,7 +272,7 @@ Definition update_ctx (size: nat) (preds: PTree.t (list positive))
               OK (PTree.set succ (PTree.set dest i g) G,
                   PTree.set pc (Iload chunk addr (map use args) dest' succ) new_code,
                   juncpoints)
-            else Error (msg "SSAvalid 3")
+            else Error (msg "SSAvalid - 3")
           | RTL.Icall sig fn args dest succ => 
             do i <- get_option (def ! pc) "" ;
             let dest' := Bij.pamr size (dest,i) in
@@ -280,7 +280,7 @@ Definition update_ctx (size: nat) (preds: PTree.t (list positive))
               OK (PTree.set succ (PTree.set dest i g) G,
                   PTree.set pc (Icall sig (map_os use fn) (map use args) dest' succ) new_code,
                   juncpoints)
-            else Error (msg "SSAvalid 4")
+            else Error (msg "SSAvalid - 4")
           | RTL.Itailcall sig fn args => 
             OK (G,
                 PTree.set pc (Itailcall sig (map_os use fn) (map use args)) new_code,
@@ -348,7 +348,7 @@ Definition build_phi_block (size:nat) (preds: PTree.t (list positive))
           | Error msg => Error msg
           | OK acc => OK (PTree.set pc new_phi_block acc)
         end
-        else Error (msg "SSAvalid 7").
+        else Error (msg "SSAvalid - 7").
 
 
 (** Computing dominator-test and so-called external parameters of an SSA function. *)
@@ -428,11 +428,11 @@ Definition typecheck_function (f: RTLdfs.function) (max_index:nat)
                         ) in
              if check_unique_def fwo && check_code_at_phipoints fwo
              then OK fwo
-             else Errors.Error (msg "SSAvalid 8") (* Function is not in SSA *)
+             else Errors.Error (msg "Code not in SSA") (* Function is not in SSA *)
            | None => Error (msg "Could not compute dominators")
            end
          end)
-      else Error (msg "SSAvalid 9") (* Program code is not well normalized *)
+      else Error (msg "Code should be normalized")
     else Error (msg "Wrong index for definition")
   else Error (msg "Wrong maximum index")
 . 
diff --git a/test/Makefile b/test/Makefile
index 504e4c53..e5546824 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,12 +1,17 @@
 include ../Makefile.config
 
-DIRS=c compression raytracer spass regression
+DIRS=c compression raytracer spass regression \
+     extra
+PICOSAT=picosat-965
+
 ifeq ($(CLIGHTGEN),true)
 DIRS+=clightgen
 endif
 
 all:
 	set -e; for i in $(DIRS); do $(MAKE) CCOMPOPTS='$(CCOMPOPTS)' -C $$i all; done
+	cd $(PICOSAT) && ./configure.sh && cd ..
+	$(MAKE) CCOMPOPTS='$(CCOMPOPTS)' -C $(PICOSAT) -f Makefile.local all
 
 test:
 	set -e; for i in $(DIRS); do $(MAKE) SIMU='$(SIMU)' -C $$i test; done
@@ -19,3 +24,4 @@ bench:
 
 clean:
 	for i in $(DIRS); do $(MAKE) -C $$i clean; done
+	$(MAKE) CCOMPOPTS='$(CCOMPOPTS)' -C $(PICOSAT) -f Makefile.local clean
diff --git a/test/extra/Makefile b/test/extra/Makefile
new file mode 100644
index 00000000..3dd08820
--- /dev/null
+++ b/test/extra/Makefile
@@ -0,0 +1,60 @@
+include ../../Makefile.config
+
+CCOMP=../../ccomp
+CCOMPFLAGS=$(CCOMPOPTS) -stdlib ../../runtime -dc -dclight -dasm $(SSA_MODE)
+
+CFLAGS=-O1 -Wall
+
+LIBS=$(LIBMATH)
+
+TIME=ocaml unix.cma ../../tools/xtime.ml -o /dev/null -mintime 2.0 -minruns 4
+
+PROGS=self-loop
+
+BENCHPROGS=
+
+all: $(PROGS:%=%.compcert)
+
+all_s: $(PROGS:%=%.s)
+
+all_gcc: $(PROGS:%=%.gcc)
+
+%.compcert: %.c
+	$(CCOMP) $(CCOMPFLAGS) -o $*.compcert $*.c $(LIBS)
+
+%.s: %.c
+	$(CCOMP) $(CCOMPFLAGS) -S $*.c
+
+%.gcc: %.c
+	$(CC) $(CFLAGS) -o $*.gcc $*.c $(LIBS)
+
+test:
+	@for i in $(BENCHPROGS); do \
+	   if $(SIMU) ./$$i.compcert | cmp -s - Results/$$i; \
+           then echo "$$i: passed"; \
+           else echo "$$i: FAILED"; exit 2; \
+	   fi; \
+         done
+
+test_gcc:
+	@for i in $(BENCHPROGS); do \
+	   if ./$$i.gcc | cmp -s - Results/$$i; \
+           then echo "$$i: passed"; \
+           else echo "$$i: FAILED"; \
+	   fi; \
+         done
+
+bench_gcc:
+	@for i in $(BENCHPROGS); do \
+	   $(TIME) -name $$i -- ./$$i.gcc; \
+         done
+
+bench:
+	@for i in $(BENCHPROGS); do \
+	   $(TIME) -name $$i -- ./$$i.compcert; \
+         done
+
+clean:
+	rm -f *.compcert *.gcc
+	rm -f *.compcert.c *.light.c *.parsed.c *.s *.o *.sdump *~
+	rm -f *.rtl.[0-9] *.ssa.[0-9] *.rtl.norm
diff --git a/test/extra/self-loop.c b/test/extra/self-loop.c
new file mode 100644
index 00000000..d810da1f
--- /dev/null
+++ b/test/extra/self-loop.c
@@ -0,0 +1,4 @@
+int main() {
+a:
+  goto a;
+}
diff --git a/test/picosat-965/LICENSE b/test/picosat-965/LICENSE
new file mode 100644
index 00000000..96739de2
--- /dev/null
+++ b/test/picosat-965/LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2006 - 2014, Armin Biere, Johannes Kepler University.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+
diff --git a/test/picosat-965/Makefile.local b/test/picosat-965/Makefile.local
new file mode 100644
index 00000000..9db5dfac
--- /dev/null
+++ b/test/picosat-965/Makefile.local
@@ -0,0 +1,62 @@
+include ../../Makefile.config
+
+CC=../../ccomp 
+CFLAGS=$(CCOMPOPTS) -stdlib ../../runtime -dparse -dclight -dasm -fstruct-return -fbitfields $(SSA_MODE)
+
+all: picosat picomcs picomus picogcnf libpicosat.a
+
+clean:
+	rm -f picosat picomcs picomus picogcnf
+	rm -f *.exe *.s *.o *.a *.so *.plist
+	rm -f makefile config.h
+	rm -f *.o *.s *.parsed.c *.light.c *.sdump
+	rm -f gmon.out *~ 
+
+analyze:
+	clang --analyze $(CFLAGS) *.c *.h
+
+picosat: libpicosat.a app.o main.o
+	$(CC) $(CFLAGS) -o $@ main.o app.o -L. -lpicosat
+
+picomcs: libpicosat.a picomcs.o
+	$(CC) $(CFLAGS) -o $@ picomcs.o -L. -lpicosat
+
+picomus: libpicosat.a picomus.o
+	$(CC) $(CFLAGS) -o $@ picomus.o -L. -lpicosat
+
+picogcnf: libpicosat.a picogcnf.o
+	$(CC) $(CFLAGS) -o $@ picogcnf.o -L. -lpicosat
+
+app.o: app.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picomcs.o: picomcs.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picomus.o: picomus.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picogcnf.o: picogcnf.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+main.o: main.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picosat.o: picosat.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+version.o: version.c config.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+config.h: makefile VERSION mkconfig.sh # and actually picosat.c
+	rm -f $@; ./mkconfig.sh > $@
+
+libpicosat.a: picosat.o version.o
+	ar rc $@ picosat.o version.o
+	ranlib $@
+
+SONAME=-Xlinker -soname -Xlinker libpicosat.so
+libpicosat.so: picosat.o version.o
+	$(CC) $(CFLAGS) -shared -o $@ picosat.o version.o $(SONAME)
+
+.PHONY: all clean
diff --git a/test/picosat-965/NEWS b/test/picosat-965/NEWS
new file mode 100644
index 00000000..7ad60b53
--- /dev/null
+++ b/test/picosat-965/NEWS
@@ -0,0 +1,162 @@
+news for release 965 since 959
+------------------------------
+
+* ADC code works again (spotted by Himanshu Jain)
+* include into R projects (with Christoph Muessel) (--rcode)
+* fixed 'undefined' + 'ptrdiff_' issues (thanks to Christoph Muessel)
+* added 'picosat_set_interrupt' and '-a <alarm>' command line option
+* fixed various issues pointed out by Stefan Hengelein:
+  - fixed incremental usage of 'picosat_adjust'
+  - added CPP fixes (STATS, NO_BINARY_CLAUSE versus TRACE mix-ups)
+  - removed redundant explicit set to zero on reset
+* fixed various usage bugs with 'picomus' (thanks to Stefan Hengelein)
+* removed '-fno-strict-aliasing' (thanks to Jerry James)
+
+news for release 959 since 953
+------------------------------
+
+* fixed header comments
+
+* fixed minor compilation issues
+
+* fixed unitialized memory access problem for 'picosat_deref_partial'
+  and another issue with partial models
+
+* added 'picosat_add_arg' and 'picosat_add_lits'
+
+* '--plain' and 'picosat_set_plain' to disable failed literal probing
+
+* new '#define PICOSAT_REENTRANT_API' in 'picosat.h'
+
+* added manager so no more global variables
+  (allows multiple instances, requires manager object)
+
+news for release 951 since 941
+------------------------------
+
+* cleaned up code (based on comments by Donald Knuth)
+
+* lreduce=O(conflicts^.5)
+
+* added 'picosat_visits' and 'picosat_decisions'
+
+* added '--partial' command line option
+
+* added 'picosat_deref_partial' and 'picosat_save_original_clauses'
+
+* added 'picomcs' as example for MSS computation
+
+news for release 941 since 936
+------------------------------
+
+* added 'picogcnf'
+
+* added All-SAT mode ('--all' command line option)
+
+* statistics include time spent in failed literal preprocessing (probing)
+
+* 'picosat_failed_context' for 'push & pop'
+   (and tested failed assumptions for 'push & pop')
+
+* 'picosat_simplify' for forced garbage collection
+
+* undefined NFL, defined NADC (= failed literals on, ADC's off)
+
+* 'picosat_push' and 'picosat_pop' (beta version)
+
+* fixed some issues related to binary clause handling and 
+  generating list of failed assumptions
+
+news for release 936 since 935
+------------------------------
+
+* simple minimal unsatisfiable core (MUS) extractor 'picomus'
+  (example for using 'picosat_mus_assumptions' and 'picosat_coreclause')
+
+* added 'picosat_mus_assumptions'
+
+* added 'picosat_{set_}propagations'
+
+* new 'int' return value for 'picosat_enable_trace_generation' to
+  check for trace code being compiled
+
+news for release 935 since 926
+------------------------------
+
+* added 'picosat_failed_assumptions' (plural)
+
+* new '-A <failedlits>' command line option
+
+* fixed failed assumption issues
+
+* added 'picosat_remove_learned'
+
+* added 'picosat_reset_{phases,scores}'
+
+* added 'picosat_set_less_important_lit'
+
+* added 'picosat_res'
+
+news for release 926 since 846
+------------------------------
+
+* random initial phase (API of 'picosat_set_default_phase' changed)
+
+* fixed accumulative failed assumption (multiple times)
+
+* fixed missing original clause in core generation with assumptions
+
+* fixed debugging code for memory allocation
+
+* shared library in addition to static library
+
+* removed potential UNKNOWN result without decision limit
+
+* added picosat_set_more_important_lit
+
+* added picosat_coreclause
+
+* propagation of binary clauses until completion
+
+* fixed API usage 'assume;sat;sat'
+
+* literals move to front (LMTF) during traversal of visited clauses
+
+* switched from inner/outer to Luby style restart scheduling
+
+* less agressive reduce schedule
+
+* replaced watched literals with head and tail pointers
+
+* add 'picosat_failed_assumption', which allows to avoid tracing and core
+  generation, if one is only interested in assumptions in the core
+
+* fixed a BUG in the generic iterator code of clauses
+  (should rarely happen unless you use a very sophisticated malloc lib)
+
+news for release 846 since 632
+------------------------------
+
+* cleaned up assumption handling (actually removed buggy optimization)
+
+* incremental core generation 
+
+* experimental 'all different constraint' handling as in our FMCAD'08 paper
+
+* new API calls: 
+
+  - picosat_add_ado_lit       (add all different object literal)
+  - picosat_deref_top_level   (deref top level assignment)
+  - picosat_changed           (check whether extension was possible)
+  - picosat_measure_all_calls (per default do not measure adding time)
+  - picosat_set_prefix        (set prefix for messages)
+
+* 64 bit port (and compilation options)
+
+* optional NVSIDS visualization code
+
+* resource controlled failed literal implementation
+
+* disconnect long clauses satisfied at lower decision level
+
+* controlling restarts
diff --git a/test/picosat-965/README b/test/picosat-965/README
new file mode 100644
index 00000000..05b84396
--- /dev/null
+++ b/test/picosat-965/README
@@ -0,0 +1,5 @@
+These are the sources of the PicoSAT solver.
+The preprocessor is not included.
+To compile run './configure.sh && make'.
+The API is document in 'picosat.h'.
+See also 'NEWS' and 'LICENSE'.
diff --git a/test/picosat-965/VERSION b/test/picosat-965/VERSION
new file mode 100644
index 00000000..aa5bea4e
--- /dev/null
+++ b/test/picosat-965/VERSION
@@ -0,0 +1 @@
+965
diff --git a/test/picosat-965/app.c b/test/picosat-965/app.c
new file mode 100644
index 00000000..8c907374
--- /dev/null
+++ b/test/picosat-965/app.c
@@ -0,0 +1,1192 @@
+#include "picosat.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define GUNZIP "gunzip -c %s"
+#define BUNZIP2 "bzcat %s"
+#define GZIP "gzip -c -f > %s"
+
+FILE * popen (const char *, const char*);
+int pclose (FILE *);
+
+static PicoSAT * picosat;
+
+static int lineno;
+static FILE *input;
+static int inputid;
+static FILE *output;
+static int verbose;
+static int sargc;
+static char ** sargv;
+static char buffer[100];
+static char *bhead = buffer;
+static const char *eob = buffer + 80;
+static FILE * incremental_rup_file;
+static signed char * sol;
+
+extern void picosat_enter (PicoSAT *);
+extern void picosat_leave (PicoSAT *);
+
+static int
+next (void)
+{
+  int res = getc (input);
+  if (res == '\n')
+    lineno++;
+
+  return res;
+}
+
+static const char *
+parse (PicoSAT * picosat, int force)
+{
+  int ch, sign, lit, vars, clauses;
+
+  lineno = 1;
+  inputid = fileno (input);
+
+SKIP_COMMENTS:
+  ch = next ();
+  if (ch == 'c')
+    {
+      while ((ch = next ()) != EOF && ch != '\n')
+	;
+      goto SKIP_COMMENTS;
+    }
+
+  if (isspace (ch))
+    goto SKIP_COMMENTS;
+
+  if (ch != 'p')
+INVALID_HEADER:
+    return "missing or invalid 'p cnf <variables> <clauses>' header";
+
+  if (!isspace (next ()))
+    goto INVALID_HEADER;
+
+  while (isspace (ch = next ()))
+    ;
+
+  if (ch != 'c' || next () != 'n' || next () != 'f' || !isspace (next ()))
+    goto INVALID_HEADER;
+
+  while (isspace (ch = next ()))
+    ;
+    
+  if (!isdigit (ch))
+    goto INVALID_HEADER;
+
+  vars = ch - '0';
+  while (isdigit (ch = next ()))
+    vars = 10 * vars + (ch - '0');
+
+  if (!isspace (ch))
+    goto INVALID_HEADER;
+
+  while (isspace (ch = next ()))
+    ;
+
+  if (!isdigit (ch))
+    goto INVALID_HEADER;
+
+  clauses = ch - '0';
+  while (isdigit (ch = next ()))
+    clauses = 10 * clauses + (ch - '0');
+
+  if (!isspace (ch) && ch != '\n' )
+    goto INVALID_HEADER;
+
+  if (verbose)
+    {
+      fprintf (output, "c parsed header 'p cnf %d %d'\n", vars, clauses);
+      fflush (output);
+    }
+
+  picosat_adjust (picosat, vars);
+
+  if (incremental_rup_file)
+    picosat_set_incremental_rup_file (picosat, incremental_rup_file, vars, clauses);
+
+  lit = 0;
+READ_LITERAL:
+  ch = next ();
+
+  if (ch == 'c')
+    {
+      while ((ch = next ()) != EOF && ch != '\n')
+	;
+      goto READ_LITERAL;
+    }
+
+  if (ch == EOF)
+    {
+      if (lit)
+	return "trailing 0 missing";
+
+      if (clauses && !force)
+	return "clause missing";
+
+      return 0;
+    }
+
+  if (isspace (ch))
+    goto READ_LITERAL;
+
+  sign = 1;
+  if (ch == '-')
+    {
+      sign = -1;
+      ch = next ();
+    }
+
+  if (!isdigit (ch))
+    return "expected number";
+
+  lit = ch - '0';
+  while (isdigit (ch = next ()))
+    lit = 10 * lit + (ch - '0');
+
+  if (!clauses && !force)
+    return "too many clauses";
+
+  if (lit)
+    {
+      if (lit > vars && !force)
+	return "maximal variable index exceeded";
+
+      lit *= sign;
+    }
+  else
+    clauses--;
+
+  picosat_add (picosat, lit);
+
+  goto READ_LITERAL;
+}
+
+static void
+bflush (void)
+{
+  *bhead = 0;
+  fputs (buffer, output);
+  fputc ('\n', output);
+  bhead = buffer;
+}
+
+static void
+printi (int i)
+{
+  char *next;
+  int l;
+
+REENTER:
+  if (bhead == buffer)
+    *bhead++ = 'v';
+
+  l = sprintf (bhead, " %d", i);
+  next = bhead + l;
+
+  if (next >= eob)
+    {
+      bflush ();
+      goto REENTER;
+    }
+  else
+    bhead = next;
+}
+
+static void
+printa (PicoSAT * picosat, int partial)
+{
+  int max_idx = picosat_variables (picosat), i, lit, val;
+
+  assert (bhead == buffer);
+
+  for (i = 1; i <= max_idx; i++)
+    {
+      if (partial)
+	{
+	  val = picosat_deref_partial (picosat, i);
+	  if (!val)
+	    continue;
+	}
+      else
+	val = picosat_deref (picosat, i);
+      lit = (val > 0) ? i : -i;
+      printi (lit);
+    }
+
+  printi (0);
+  if (bhead > buffer)
+    bflush ();
+}
+
+static void
+blocksol (PicoSAT * picosat)
+{
+  int max_idx = picosat_variables (picosat), i;
+
+  if (!sol)
+    {
+      sol = malloc (max_idx + 1);
+      memset (sol, 0, max_idx + 1);
+    }
+
+  for (i = 1; i <= max_idx; i++)
+    sol[i] = (picosat_deref (picosat, i) > 0) ? 1 : -1;
+
+  for (i = 1; i <= max_idx; i++)
+    picosat_add (picosat, (sol[i] < 0) ? i : -i);
+
+  picosat_add (picosat, 0);
+}
+
+static int
+has_suffix (const char *str, const char *suffix)
+{
+  const char *tmp = strstr (str, suffix);
+  if (!tmp)
+    return 0;
+
+  return str + strlen (str) - strlen (suffix) == tmp;
+}
+
+static void
+write_core_variables (PicoSAT * picosat, FILE * file)
+{
+  int i, max_idx = picosat_variables (picosat), count = 0;
+  for (i = 1; i <= max_idx; i++)
+    if (picosat_corelit (picosat, i))
+      {
+	fprintf (file, "%d\n", i);
+	count++;
+      }
+
+  if (verbose)
+    fprintf (output, "c found and wrote %d core variables\n", count);
+}
+
+static int
+next_assumption (int start)
+{
+  char * arg, c;
+  int res;
+  res = start + 1;
+  while (res < sargc)
+  {
+    arg = sargv[res++];
+    if (!strcmp (arg, "-a"))
+      {
+	assert (res < sargc);
+	break;
+      }
+
+    if (arg[0] == '-') {
+      c = arg[1];
+      if (c == 'l' || c == 'i' || c == 's' || c == 'o' || c == 't' ||
+	  c == 'T' || c == 'r' || c == 'R' || c == 'c' || c == 'V' ||
+	  c == 'U' || c == 'A') res++;
+    }
+  }
+  if (res >= sargc) res = 0;
+  return res;
+}
+
+static void
+write_failed_assumptions (PicoSAT * picosat, FILE * file)
+{
+  int i, lit, count = 0;
+#ifndef NDEBUG
+  int max_idx = picosat_variables (picosat);
+#endif
+  i = 0;
+  while ((i = next_assumption (i))) {
+    lit = atoi (sargv[i]);
+    if (!picosat_failed_assumption (picosat, lit)) continue;
+    fprintf (file, "%d\n", lit);
+    count++;
+  }
+  if (verbose)
+    fprintf (output, "c found and wrote %d failed assumptions\n", count);
+#ifndef NDEBUG
+  for (i = 1; i <= max_idx; i++)
+    if (picosat_failed_assumption (picosat, i))
+      count--;
+#endif
+  assert (!count);
+}
+
+static void
+write_to_file (PicoSAT * picosat, 
+               const char *name, 
+               const char *type,
+	       void (*writer) (PicoSAT *, FILE *))
+{
+  int pclose_file, zipped = has_suffix (name, ".gz");
+  FILE *file;
+  char *cmd;
+
+  if (zipped)
+    {
+      cmd = malloc (strlen (GZIP) + strlen (name));
+      sprintf (cmd, GZIP, name);
+      file = popen (cmd, "w");
+      free (cmd);
+      pclose_file = 1;
+    }
+  else
+    {
+      file = fopen (name, "w");
+      pclose_file = 0;
+    }
+
+  if (file)
+    {
+      if (verbose)
+	fprintf (output,
+		 "c\nc writing %s%s to '%s'\n",
+		 zipped ? "gzipped " : "", type, name);
+
+      writer (picosat, file);
+
+      if (pclose_file)
+	pclose (file);
+      else
+	fclose (file);
+    }
+  else
+    fprintf (output, "*** picosat: can not write to '%s'\n", name);
+}
+
+static int catched;
+
+static void (*sig_int_handler);
+static void (*sig_segv_handler);
+static void (*sig_abrt_handler);
+static void (*sig_term_handler);
+#ifndef NALLSIGNALS
+static void (*sig_kill_handler);
+static void (*sig_xcpu_handler);
+static void (*sig_xfsz_handler);
+#endif
+
+static void
+resetsighandlers (void)
+{
+  (void) signal (SIGINT, sig_int_handler);
+  (void) signal (SIGSEGV, sig_segv_handler);
+  (void) signal (SIGABRT, sig_abrt_handler);
+  (void) signal (SIGTERM, sig_term_handler);
+#ifndef NALLSIGNALS
+  (void) signal (SIGKILL, sig_kill_handler);
+  (void) signal (SIGXCPU, sig_xcpu_handler);
+  (void) signal (SIGXFSZ, sig_xfsz_handler);
+#endif
+}
+
+static int time_limit_in_seconds;
+static void (*sig_alarm_handler);
+static int ought_to_be_interrupted, interrupt_notified;
+
+static void
+alarm_triggered (int sig)
+{
+  (void) sig;
+  assert (sig == SIGALRM);
+  assert (time_limit_in_seconds);
+  assert (!ought_to_be_interrupted);
+  ought_to_be_interrupted = 1;
+  assert (!interrupt_notified);
+}
+
+static int
+interrupt_call_back (void * dummy)
+{
+  (void) dummy;
+  if (!ought_to_be_interrupted)
+    return 0;
+  if (!interrupt_notified)
+    {
+      if (verbose)
+	{
+	  picosat_message (picosat, 1, "");
+	  picosat_message (picosat, 1,
+	    "*** TIME LIMIT OF %d SECONDS REACHED ***",
+	    time_limit_in_seconds);
+	  picosat_message (picosat, 1, "");
+	}
+      interrupt_notified = 1;
+    }
+  return 1;
+}
+
+static void
+setalarm ()
+{
+  assert (time_limit_in_seconds > 0);
+  sig_alarm_handler = signal (SIGALRM, alarm_triggered);
+  alarm (time_limit_in_seconds);
+  assert (picosat);
+  picosat_set_interrupt (picosat, 0, interrupt_call_back);
+}
+
+static void
+resetalarm ()
+{
+  assert (time_limit_in_seconds > 0);
+  (void) signal (SIGALRM, sig_term_handler);
+}
+
+static void
+message (int sig)
+{
+  picosat_message (picosat, 1, "");
+  picosat_message (picosat, 1, "*** CAUGHT SIGNAL %d ***", sig);
+  picosat_message (picosat, 1, "");
+}
+
+static void
+catch (int sig)
+{
+  if (!catched)
+    {
+      message (sig);
+      catched = 1;
+      picosat_stats (picosat);
+      message (sig);
+    }
+
+  resetsighandlers ();
+  raise (sig);
+}
+
+static void
+setsighandlers (void)
+{
+  sig_int_handler = signal (SIGINT, catch);
+  sig_segv_handler = signal (SIGSEGV, catch);
+  sig_abrt_handler = signal (SIGABRT, catch);
+  sig_term_handler = signal (SIGTERM, catch);
+#ifndef NALLSIGNALS
+  sig_kill_handler = signal (SIGKILL, catch);
+  sig_xcpu_handler = signal (SIGXCPU, catch);
+  sig_xfsz_handler = signal (SIGXFSZ, catch);
+#endif
+}
+
+#define USAGE \
+"usage: picosat [ <option> ... ] [ <input> ]\n" \
+"\n" \
+"where <option> is one of the following\n" \
+"\n" \
+"  -h           print this command line option summary and exit\n" \
+"  --version    print version and exit\n" \
+"  --config     print build configuration and exit\n" \
+"\n" \
+"  -v           enable verbose output\n" \
+"  -f           ignore invalid header\n" \
+"  -n           do not print satisfying assignment\n" \
+"  -p           print formula in DIMACS format and exit\n" \
+"  --plain      disable preprocessing (failed literal probing)\n" \
+"  -a <lit>     start with an assumption\n" \
+"  -l <limit>   set decision limit (no limit per default)\n" \
+"  -L <limit>   set time limit in seconds (no limit per default)\n" \
+"  -P <limit>   set propagation limit (no limit per default)\n" \
+"  -i [0-3]     [0-3]=[FALSE,TRUE,JWH,RAND] initial phase (default 2=JWH)\n" \
+"  -s <seed>    set random number generator seed (default 0)\n" \
+"  -o <output>  set output file (<stdout> per default)\n" \
+"  -t <trace>   generate compact proof trace file\n" \
+"  -T <trace>   generate extended proof trace file\n" \
+"  -r <trace>   generate reverse unit propagation proof file\n" \
+"  -R <trace>   generate reverse unit propagation proof file incrementally\n" \
+"  -c <core>    generate clausal core file in DIMACS format\n" \
+"  -V <core>    generate file listing core variables\n" \
+"  -U <core>    generate file listing used variables\n" \
+"  -A <core>    generate file listing failed assumptions\n" \
+"\n" \
+"  --all        enumerate all solutions\n" \
+"  --partial    generate and print only partial assignment\n" \
+"\n" \
+"and <input> is an optional input file in DIMACS format.\n"
+
+int
+picosat_main (int argc, char **argv)
+{
+  int res, done, err, print_satisfying_assignment, force, print_formula;
+  const char *compact_trace_name, *extended_trace_name, * rup_trace_name;
+  int assumption, assumptions, defaultphase, allsat, partial, plain;
+  const char * clausal_core_name, * variable_core_name;
+  const char *input_name, *output_name;
+  const char * failed_assumptions_name;
+  int close_input, pclose_input;
+  long long propagation_limit;
+  int i, decision_limit;
+  double start_time;
+  long long sols;
+  unsigned seed;
+  FILE *file;
+  int trace;
+
+  start_time = picosat_time_stamp ();
+
+  sargc = argc;
+  sargv = argv;
+
+  clausal_core_name = 0;
+  variable_core_name = 0;
+  failed_assumptions_name = 0;
+  output_name = 0;
+  compact_trace_name = 0;
+  extended_trace_name = 0;
+  rup_trace_name = 0;
+  incremental_rup_file = 0;
+  close_input = 0;
+  pclose_input = 0;
+  input_name = "<stdin>";
+  input = stdin;
+  output = stdout;
+  verbose = 0;
+  done = err = 0;
+  decision_limit = -1;
+  propagation_limit = -1;
+  defaultphase = 2;
+  assumptions = 0;
+  force = 0;
+  allsat = 0;
+  partial = 0;
+  trace = 0;
+  plain = 0;
+  seed = 0;
+  sols= 0;
+
+  picosat = 0;
+
+  print_satisfying_assignment = 1;
+  print_formula = 0;
+
+  for (i = 1; !done && !err && i < argc; i++)
+    {
+      if (!strcmp (argv[i], "-h"))
+	{
+	  fputs (USAGE, output);
+	  done = 1;
+	}
+      else if (!strcmp (argv[i], "--version"))
+	{
+	  fprintf (output, "%s\n", picosat_version ());
+	  done = 1;
+	}
+      else if (!strcmp (argv[i], "--config"))
+	{
+	  fprintf (output, "%s\n", picosat_config ());
+	  done = 1;
+	}
+      else if (!strcmp (argv[i], "-v"))
+	{
+	  verbose++;
+	}
+      else if (!strcmp (argv[i], "--plain"))
+	{
+	  plain = 1;
+	}
+      else if (!strcmp (argv[i], "-f"))
+	{
+	  force = 1;
+	}
+      else if (!strcmp (argv[i], "-n"))
+	{
+	  print_satisfying_assignment = 0;
+	}
+      else if (!strcmp (argv[i], "--partial"))
+	{
+	  partial = 1;
+	}
+      else if (!strcmp (argv[i], "-p"))
+	{
+	  print_formula = 1;
+	}
+      else if (!strcmp (argv[i], "-l"))
+	{
+	  if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument to '-l' missing\n");
+	      err = 1;
+	    }
+	  else
+	    decision_limit = atoi (argv[i]);
+	}
+      else if (!strcmp (argv[i], "-L"))
+	{
+	  if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument to '-L' missing\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      time_limit_in_seconds = atoi (argv[i]);
+	      if (time_limit_in_seconds <= 0)
+		{
+		  fprintf (output, "*** picosat: invalid '-L' argument\n");
+		  err = 1;
+		}
+	    }
+	}
+      else if (!strcmp (argv[i], "-P"))
+	{
+	  if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument to '-P' missing\n");
+	      err = 1;
+	    }
+	  else
+	    propagation_limit = atoll (argv[i]);
+	}
+      else if (!strcmp (argv[i], "-i"))
+	{
+	  if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument to '-i' missing\n");
+	      err = 1;
+	    }
+	  else if (!argv[i][1] && ('0' <= argv[i][0] && argv[i][0] <= '3'))
+	    {
+	      defaultphase = argv[i][0] - '0';
+	    }
+	  else
+	    {
+	      fprintf (output, "*** picosat: invalid argument to '-i'\n");
+	      err = 1;
+	    }
+	}
+      else if (!strcmp (argv[i], "-a"))
+	{
+	  if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument to '-a' missing\n");
+	      err = 1;
+	    }
+	  else if (!atoi (argv[i]))
+	    {
+	      fprintf (output, "*** picosat: argument to '-a' zero\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      /* Handle assumptions further down
+	       */
+	      assumptions++;
+	    }
+	}
+      else if (!strcmp (argv[i], "--all"))
+	{
+	  allsat = 1;
+	}
+      else if (!strcmp (argv[i], "-s"))
+	{
+	  if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument to '-s' missing\n");
+	      err = 1;
+	    }
+	  else
+	    seed = atoi (argv[i]);
+	}
+      else if (!strcmp (argv[i], "-o"))
+	{
+	  if (output_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple output files '%s' and '%s'\n",
+		       output_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-o' missing\n");
+	      err = 1;
+	    }
+	  else if (!(file = fopen (argv[i], "w")))
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "can not write output file '%s'\n", argv[i]);
+	      err = 1;
+	    }
+	  else
+	    {
+	      output_name = argv[i];
+	      output = file;
+	    }
+	}
+      else if (!strcmp (argv[i], "-t"))
+	{
+	  if (compact_trace_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple compact trace files '%s' and '%s'\n",
+		       compact_trace_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-t' missing\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      compact_trace_name = argv[i];
+	      trace = 1;
+	    }
+	}
+      else if (!strcmp (argv[i], "-T"))
+	{
+	  if (extended_trace_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple extended trace files '%s' and '%s'\n",
+		       extended_trace_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-T' missing\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      extended_trace_name = argv[i];
+	      trace = 1;
+	    }
+	}
+      else if (!strcmp (argv[i], "-r"))
+	{
+	  if (rup_trace_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple RUP trace files '%s' and '%s'\n",
+		       rup_trace_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-r' missing\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      rup_trace_name = argv[i];
+	      trace = 1;
+	    }
+	}
+      else if (!strcmp (argv[i], "-R"))
+	{
+	  if (rup_trace_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple RUP trace files '%s' and '%s'\n",
+		       rup_trace_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-R' missing\n");
+	      err = 1;
+	    }
+	  else if (!(file = fopen (argv[i], "w")))
+	    {
+	      fprintf (output,
+		       "*** picosat: can not write to '%s'\n", argv[i]);
+	      err = 1;
+	    }
+	  else
+	    {
+	      rup_trace_name = argv[i];
+	      incremental_rup_file = file;
+	    }
+	}
+      else if (!strcmp (argv[i], "-c"))
+	{
+	  if (clausal_core_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple clausal core files '%s' and '%s'\n",
+		       clausal_core_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-c' missing\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      clausal_core_name = argv[i];
+	      trace = 1;
+	    }
+	}
+      else if (!strcmp (argv[i], "-V"))
+	{
+	  if (variable_core_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple variable core files '%s' and '%s'\n",
+		       variable_core_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-V' missing\n");
+	      err = 1;
+	    }
+	  else
+	    {
+	      variable_core_name = argv[i];
+	      trace = 1;
+	    }
+	}
+      else if (!strcmp (argv[i], "-A"))
+	{
+	  if (failed_assumptions_name)
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "multiple failed assumptions files '%s' and '%s'\n",
+		       failed_assumptions_name, argv[i]);
+	      err = 1;
+	    }
+	  else if (++i == argc)
+	    {
+	      fprintf (output, "*** picosat: argument ot '-A' missing\n");
+	      err = 1;
+	    }
+	  else
+	    failed_assumptions_name = argv[i];
+	}
+      else if (argv[i][0] == '-')
+	{
+	  fprintf (output,
+		   "*** picosat: "
+		   "unknown command line option '%s' (try '-h')\n", argv[i]);
+	  err = 1;
+	}
+      else if (close_input || pclose_input)
+	{
+	  fprintf (output,
+		   "*** picosat: "
+		   "multiple input files '%s' and '%s'\n",
+		   input_name, argv[i]);
+	  err = 1;
+	}
+      else if (has_suffix (argv[i], ".gz"))
+	{
+	  char *cmd = malloc (strlen (GUNZIP) + strlen (argv[i]));
+	  sprintf (cmd, GUNZIP, argv[i]);
+	  if ((file = popen (cmd, "r")))
+	    {
+	      input_name = argv[i];
+	      pclose_input = 1;
+	      input = file;
+	    }
+	  else
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "can not read compressed input file '%s'\n", argv[i]);
+	      err = 1;
+	    }
+	  free (cmd);
+	}
+      else if (has_suffix (argv[i], ".bz2"))
+	{
+	  char *cmd = malloc (strlen (BUNZIP2) + strlen (argv[i]));
+	  sprintf (cmd, BUNZIP2, argv[i]);
+	  if ((file = popen (cmd, "r")))
+	    {
+	      input_name = argv[i];
+	      pclose_input = 1;
+	      input = file;
+	    }
+	  else
+	    {
+	      fprintf (output,
+		       "*** picosat: "
+		       "can not read compressed input file '%s'\n", argv[i]);
+	      err = 1;
+	    }
+	  free (cmd);
+	}
+      else if (!(file = fopen (argv[i], "r")))	/* TODO .gz ? */
+	{
+	  fprintf (output,
+		   "*** picosat: can not read input file '%s'\n", argv[i]);
+	  err = 1;
+	}
+      else
+	{
+	  input_name = argv[i];
+	  close_input = 1;
+	  input = file;
+	}
+    }
+
+  if (allsat && partial)
+    {
+      fprintf (output,
+	       "*** picosat: can not combine '--all' and '--partial'");
+      err = 1;
+    }
+
+  res = PICOSAT_UNKNOWN;
+
+  if (!done && !err)
+    {
+      const char *err_msg;
+
+      if (verbose)
+	{
+	  fprintf (output,
+		   "c PicoSAT SAT Solver Version %s\n",
+		   picosat_version ());
+
+	  fprintf (output, "c %s\n", picosat_copyright ());
+	  fprintf (output, "c %s\n", picosat_config ());
+	}
+
+      picosat = picosat_init ();
+
+      if (verbose)
+	setsighandlers ();
+
+      if (time_limit_in_seconds)
+	setalarm ();
+
+      picosat_enter (picosat);
+
+      if (output_name)
+	picosat_set_output (picosat, output);
+
+      picosat_set_verbosity (picosat, verbose);
+      picosat_set_plain (picosat, plain);
+
+      if (verbose) fputs ("c\n", output);
+
+      if (trace)
+	{
+	  if (verbose)
+	    fprintf (output, "c tracing proof\n");
+	  picosat_enable_trace_generation (picosat);
+	}
+
+      if (defaultphase)
+	{
+	  if (verbose)
+	    fprintf (output, "c using %d as default phase\n", defaultphase);
+	  picosat_set_global_default_phase (picosat, defaultphase);
+	}
+
+      if (propagation_limit >= 0)
+	{
+	  if (verbose)
+	    fprintf (output, "c propagation limit of %lld propagations\n",
+	             propagation_limit);
+	  picosat_set_propagation_limit (picosat, 
+	    (unsigned long long) propagation_limit);
+	}
+
+      if (partial) 
+	{
+	  if (verbose)
+	    fprintf (output, 
+	      "c saving original clauses for partial assignment\n");
+
+	  picosat_save_original_clauses (picosat);
+	}
+
+      if (verbose)
+	fprintf (output, "c\nc parsing %s\n", input_name);
+
+      if (verbose)
+	fflush (output);
+
+      if ((err_msg = parse (picosat, force)))
+	{
+	  fprintf (output, "%s:%d: %s\n", input_name, lineno, err_msg);
+	  err = 1;
+	}
+      else
+	{
+NEXT_SOLUTION:
+	  if (assumptions)
+	    {
+	      i = 0;
+	      while ((i = next_assumption (i)))
+		{
+		  assert (i < argc);
+		  assumption = atoi (argv[i]);
+		  assert (assumption);
+
+		  picosat_assume (picosat, assumption);
+
+		  if (verbose)
+		    fprintf (output, "c assumption %d\n", assumption);
+		}
+	    }
+
+	  if (print_formula)
+	    {
+	      picosat_print (picosat, output);
+	    }
+	  else
+	    {
+	      if (verbose)
+		fprintf (output,
+			 "c initialized %u variables\n"
+			 "c found %u non trivial clauses\n",
+			 picosat_variables (picosat),
+			 picosat_added_original_clauses (picosat));
+
+	      picosat_set_seed (picosat, seed);
+	      if (verbose)
+		fprintf (output,
+			 "c\nc random number generator seed %u\n", 
+			 seed);
+
+	      res = picosat_sat (picosat, decision_limit);
+
+	      if (res == PICOSAT_UNSATISFIABLE)
+		{
+
+		  if (allsat)
+		    fprintf (output, "s SOLUTIONS %lld\n", sols);
+		  else
+		    fputs ("s UNSATISFIABLE\n", output);
+
+		  fflush (output);
+
+		  if (compact_trace_name)
+		    write_to_file (picosat,
+		                   compact_trace_name,
+				   "compact trace", 
+				   picosat_write_compact_trace);
+
+		  if (extended_trace_name)
+		    write_to_file (picosat,
+		                   extended_trace_name,
+				   "extended trace", 
+				   picosat_write_extended_trace);
+
+		  if (!incremental_rup_file && rup_trace_name)
+		    write_to_file (picosat,
+		                   rup_trace_name,
+				   "rup trace", 
+				   picosat_write_rup_trace);
+
+		  if (clausal_core_name)
+		    write_to_file (picosat,
+		                   clausal_core_name, 
+				   "clausal core",
+				   picosat_write_clausal_core);
+
+		  if (variable_core_name)
+		    write_to_file (picosat,
+		                   variable_core_name, 
+				   "variable core",
+				   write_core_variables);
+
+		  if (failed_assumptions_name)
+		    write_to_file (picosat,
+		                   failed_assumptions_name,
+		                   "failed assumptions", 
+				   write_failed_assumptions);
+		}
+	      else if (res == PICOSAT_SATISFIABLE)
+		{
+	          if (allsat)
+		    {
+		      sols++;
+		      if (verbose)
+			fprintf (output, "c\nc solution %lld\nc\n", sols);
+		    }
+
+		  if (!allsat || print_satisfying_assignment)
+		    fputs ("s SATISFIABLE\n", output);
+
+		  if (!allsat || verbose || print_satisfying_assignment)
+		    fflush (output);
+
+		  if (print_satisfying_assignment)
+		    printa (picosat, partial);
+
+		  if (allsat)
+		    {
+		      blocksol (picosat);
+		      goto NEXT_SOLUTION;
+		    }
+		}
+	      else
+		{
+		  fputs ("s UNKNOWN\n", output);
+
+		  if (allsat && verbose)
+		    fprintf (output,
+			     "c\nc limit reached after %lld solutions\n",
+			     sols);
+		  fflush (output);
+		}
+	    }
+	}
+
+      if (!err && verbose)
+	{
+	  fputs ("c\n", output);
+	  picosat_stats (picosat);
+	  fprintf (output,
+	           "c %.1f seconds total run time\n",
+		   picosat_time_stamp () - start_time);
+	}
+
+      if (sol)
+	{
+	  free (sol);
+	  sol = 0;
+	}
+
+      picosat_leave (picosat);
+
+      if (time_limit_in_seconds)
+	resetalarm ();
+
+      if (verbose)
+	resetsighandlers ();
+
+      picosat_reset (picosat);
+    }
+
+  if (incremental_rup_file)
+    fclose (incremental_rup_file);
+
+  if (close_input)
+    fclose (input);
+
+  if (pclose_input)
+    pclose (input);
+
+  if (output_name)
+    fclose (output);
+
+  return res;
+}
diff --git a/test/picosat-965/configure.sh b/test/picosat-965/configure.sh
new file mode 100755
index 00000000..a82cfe87
--- /dev/null
+++ b/test/picosat-965/configure.sh
@@ -0,0 +1,150 @@
+#!/bin/sh
+
+satcompetition=no
+
+log=no
+debug=no
+stats=undefined
+trace=undefined
+static=yes
+shared=no
+thirtytwobit=no
+static=no
+rcode=no
+
+while [ $# -gt 0 ]
+do
+  case $1 in
+    -g|--debug) debug=yes;;
+    -O|--optimize) debug=no;;
+    -l|--log) log=yes;;
+    -s|--stats) stats=yes;;
+    -t|--trace) trace=yes;;
+    --no-stats) stats=no;;
+    --no-trace) trace=no;;
+    --no-rcode) rcode=no;;
+    --rcode) rcode=yes;;
+    -32|--32|-m32) thirtytwobit=yes;;
+    -static|--static) static=yes;;
+    -shared|--shared) shared=yes;;
+    *) cat <<EOF
+usage: ./configure.sh [<option> ...]
+
+where <option> is one of the following:
+
+  -g|--debug           include debugging code and symbols
+  -O|--optimize        optimized compilation (default)
+  -l|--log             add low level logging code (default with '-g')
+  -s|--stats           more expensive statististcs (default with '-g')
+  -t|--trace           trace generation (more memory, default with '-g')
+  --no-stats           disable expensive stats
+  --no-trace           enable trace generation
+  -32|--32|-m32        compile for 32 bit machine even on 64 bit host
+  -rcode|--no-rcode    enable/disable compatibility for used in R exension
+  -static|--static     produce static binary
+  -shared|--shared     produce shared library
+EOF
+exit 1
+;;
+  esac
+shift
+done
+
+echo "version ... `cat VERSION`"
+
+if [ $satcompetition = yes ]
+then
+  debug=no
+  stats=no
+  trace=no
+  thirtytwobit=yes
+  static=yes
+  shared=no
+fi
+
+echo "debug ... $debug"
+echo "log ... $log"
+
+[ $stats = undefined ] && stats=$debug
+echo "stats ... $stats"
+
+[ $trace = undefined ] && trace=$debug
+echo "trace ... $trace"
+
+echo "static ... $static"
+
+echo "shared ... $shared"
+
+[ "X$CC" = X ] && CC=gcc
+
+if [ X"$CFLAGS" = X ]
+then
+  case X"$CC" in
+    *wine*|*mingw*) CFLAGS="-DNGETRUSAGE -DNALLSIGNALS";;
+    *);;
+  esac
+  [ $log = yes ] && CFLAGS="$CFLAGS -DLOGGING"
+  [ $stats = yes ] && CFLAGS="$CFLAGS -DSTATS"
+  [ $trace = yes ] && CFLAGS="$CFLAGS -DTRACE"
+  [ $static = yes ] && CFLAGS="$CFLAGS -static"
+  [ $rcode = yes ] && CFLAGS="$CFLAGS -DRCODE"
+  case X"$CC" in
+    X*gcc*)
+      CFLAGS="$CFLAGS -Wall -Wextra"
+      [ $thirtytwobit = yes ] && CFLAGS="$CFLAGS -m32"
+      if [ $debug = yes ]
+      then
+        CFLAGS="$CFLAGS -g3 -ggdb"
+      else
+	CFLAGS="$CFLAGS -DNDEBUG -O3"
+      fi
+      ;;
+    *)
+      if [ $debug = yes ]
+      then
+        CFLAGS="$CFLAGS -g"
+      else
+        CFLAGS="$CFLAGS -O"
+      fi
+      ;;
+  esac
+fi
+
+if [ $rcode = yes ]
+then
+  for rdoth in /usr/share/R/include/R.h $RINC undefined
+  do
+    [ -f $rdoth ] && break
+  done
+  if [ $rdoth = undefined ]
+  then
+    echo "R.h ... not found (add '-I' manually or 'RHEADER=...  ./configure')"
+  else
+    RINC="-I`dirname $rdoth`"
+    CFLAGS="$CFLAGS $RINC"
+    echo "R.h ... added '$RINC' include directive"
+  fi
+  TARGETS="libpicosat.a"
+else
+  TARGETS="picosat picomcs picomus picogcnf libpicosat.a"
+fi
+
+if [ $shared = yes ]
+then
+  TARGETS="$TARGETS libpicosat.so"
+  CFLAGS="$CFLAGS -fPIC"
+fi
+echo "targets ... $TARGETS"
+
+echo "cc ... $CC"
+
+echo "cflags ... $CFLAGS"
+
+printf "makefile ..."
+rm -f makefile
+sed \
+  -e "s,@CC@,$CC," \
+  -e "s,@CFLAGS@,$CFLAGS," \
+  -e "s,@TARGETS@,$TARGETS," \
+makefile.in > makefile
+echo " done"
diff --git a/test/picosat-965/main.c b/test/picosat-965/main.c
new file mode 100644
index 00000000..03fad79f
--- /dev/null
+++ b/test/picosat-965/main.c
@@ -0,0 +1,7 @@
+int picosat_main (int, char **);
+
+int
+main (int argc, char **argv)
+{
+  return picosat_main (argc, argv);
+}
diff --git a/test/picosat-965/makefile.in b/test/picosat-965/makefile.in
new file mode 100644
index 00000000..8e0e7403
--- /dev/null
+++ b/test/picosat-965/makefile.in
@@ -0,0 +1,59 @@
+CC=@CC@
+CFLAGS=@CFLAGS@
+
+all: @TARGETS@
+
+clean:
+	rm -f picosat picomcs picomus picogcnf
+	rm -f *.exe *.s *.o *.a *.so *.plist
+	rm -f makefile config.h
+	rm -f gmon.out *~ 
+
+analyze:
+	clang --analyze $(CFLAGS) *.c *.h
+
+picosat: libpicosat.a app.o main.o
+	$(CC) $(CFLAGS) -o $@ main.o app.o -L. -lpicosat
+
+picomcs: libpicosat.a picomcs.o
+	$(CC) $(CFLAGS) -o $@ picomcs.o -L. -lpicosat
+
+picomus: libpicosat.a picomus.o
+	$(CC) $(CFLAGS) -o $@ picomus.o -L. -lpicosat
+
+picogcnf: libpicosat.a picogcnf.o
+	$(CC) $(CFLAGS) -o $@ picogcnf.o -L. -lpicosat
+
+app.o: app.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picomcs.o: picomcs.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picomus.o: picomus.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picogcnf.o: picogcnf.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+main.o: main.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+picosat.o: picosat.c picosat.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+version.o: version.c config.h makefile
+	$(CC) $(CFLAGS) -c $<
+
+config.h: makefile VERSION mkconfig.sh # and actually picosat.c
+	rm -f $@; ./mkconfig.sh > $@
+
+libpicosat.a: picosat.o version.o
+	ar rc $@ picosat.o version.o
+	ranlib $@
+
+SONAME=-Xlinker -soname -Xlinker libpicosat.so
+libpicosat.so: picosat.o version.o
+	$(CC) $(CFLAGS) -shared -o $@ picosat.o version.o $(SONAME)
+
+.PHONY: all clean
diff --git a/test/picosat-965/mkconfig.sh b/test/picosat-965/mkconfig.sh
new file mode 100755
index 00000000..621210b9
--- /dev/null
+++ b/test/picosat-965/mkconfig.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+die () {
+   echo "*** mkconfig.sh: $*" 1>&2
+   exit 1
+}
+
+[ -f makefile ] || die "can not find 'makefile'"
+
+sed \
+  -e '/^C[A-Z]*=/!d' \
+  -e 's,^,#define PICOSAT_,' \
+  -e 's,= *, ",' \
+  -e 's,$,",' \
+  makefile
+
+id=""
+if [ -d .git -a -f .git/HEAD ]
+then
+  head="`awk 'NF == 1' .git/HEAD`"
+  if [ x"$head" = x ]
+  then
+    head="`awk '{print $2}' .git/HEAD`"
+    if [ ! x"$head" = x -a -f ".git/$head" ]
+    then
+      id=" `cat .git/$head`"
+    fi
+  else
+    id=" $head"
+  fi
+fi
+
+echo "#define PICOSAT_VERSION \"`cat VERSION`$id\""
+
+exit 0
diff --git a/test/picosat-965/picogcnf.c b/test/picosat-965/picogcnf.c
new file mode 100644
index 00000000..4d91bfae
--- /dev/null
+++ b/test/picosat-965/picogcnf.c
@@ -0,0 +1,165 @@
+/****************************************************************************
+Copyright (c) 2011-2012, Armin Biere, Johannes Kepler University.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+****************************************************************************/
+
+#include "picosat.h"
+
+#include <stdio.h>
+#include <assert.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <limits.h>
+
+#if 1
+#define LOG(ARGS...) do { } while (0)
+#else
+#define LOG(ARGS...) do { printf (##ARGS); } while (0)
+#endif
+
+static int reductions, ngroups;
+
+static PicoSAT * ps;
+
+static void die (const char * fmt, ...) {
+  va_list ap;
+  fprintf (stderr, "*** picogcnf: ");
+  va_start (ap, fmt);
+  vfprintf (stderr, fmt, ap);
+  va_end (ap);
+  fputc ('\n', stderr);
+  exit (1);
+}
+
+static void msg (const char * fmt, ...) {
+  va_list ap;
+  printf ("c [picogcnf] %.2f seconds: ", picosat_time_stamp ());
+  va_start (ap, fmt);
+  vprintf (fmt, ap);
+  va_end (ap);
+  fputc ('\n', stdout);
+  fflush (stdout);
+}
+
+static double percent (double a, double b) { return b?100.0*a/b:0.0; }
+
+static void callback (void * dummy, const int * mus) {
+  int remaining;
+  const int * p;
+  (void) dummy;
+  remaining = 0;
+  for (p = mus; *p; p++) remaining++;
+  assert (remaining <= ngroups);
+  msg ("<%d> reduction to %d out of %d (%.0f%%)",
+       ++reductions, remaining, ngroups, percent (remaining, ngroups));
+}
+
+int main (int argc, char ** argv) {
+  int ch, nvars, sclauses, nclauses, sign, lit, group, res;
+  const int * mus, * p;
+  FILE * file;
+  if (argc != 2) die ("usage: picogcnf <gcnf-file>");
+  if (!(file = fopen (argv[1], "r"))) die ("can not read '%s'", argv[1]);
+  ps = picosat_init ();
+HEADER:
+  ch = getc (file);
+  if (ch == 'c') {
+    while ((ch = getc (file)) != '\n')
+      if (ch == EOF) die ("unexpected EOF");
+    goto HEADER;
+  }
+  if (ch != 'p' || 
+      getc (file) != ' ' ||
+      fscanf (file, "gcnf %d %d %d", &nvars, &sclauses, &ngroups) != 3)
+    die ("invalid header");
+  nclauses = lit = 0;
+  group = INT_MAX;
+  LOG ("p gcnf %d %d %d\n", nvars, sclauses, ngroups);
+LIT:
+  ch = getc (file);
+  if (ch == EOF) {
+    if (lit) die ("zero missing");
+    if (nclauses < sclauses) die ("clauses missing");
+    goto DONE;
+  }
+  if (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r') goto LIT;
+  if (lit) {
+    if (ch == '-') {
+      sign = -1;
+      ch = getc (file);
+    } else sign = 1;
+    lit = ch - '0';
+    while (isdigit (ch = getc (file)))
+      lit = 10 * lit + ch - '0';
+    if (lit > nvars) die ("maximum variable exceeded");
+    lit *= sign;
+    if (lit) {
+      LOG ("%d ", lit);
+    } else {
+      LOG ("0\n");
+      group = INT_MAX;
+      nclauses++;
+    }
+    picosat_add (ps, lit);
+  } else if (ch == '{') {
+    if (nclauses == sclauses) die ("too many clauses");
+    if (group < INT_MAX) die ("multiple groups per clause");
+GROUP:
+    ch = getc (file);
+    if (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r') goto GROUP;
+    if (!isdigit (ch)) die ("group does not start with digit");
+    group = ch - '0';
+    while (isdigit (ch = getc (file)))
+      group = 10 * group + (ch - '0');
+    if (group > ngroups) die ("maximal group exceeded");
+    while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r')
+      ch = getc (file);
+    if (ch != '}') die ("expected '}'");
+    LOG ("{%d} ", group);
+    if (group) picosat_add (ps, -(nvars + group));
+    lit = INT_MAX;
+  } else die ("expected '{'");
+  goto LIT;
+DONE:
+  fclose (file);
+  for (lit = nvars + 1; lit <= nvars + ngroups; lit++) picosat_assume (ps, lit);
+  res = picosat_sat (ps, -1);
+  msg ("first call to SAT solver returned");
+  if (res == 10) printf ("s SATISFIABLE\n");
+  else if (res == 20) printf ("s UNSATISFIABLE\n");
+  else printf ("s UNKNOWN\n");
+  fflush (stdout);
+  if (res == 20) {
+    mus = picosat_mus_assumptions (ps, 0, callback, 1);
+    assert (mus);
+    printf ("v");
+    for (p = mus; (lit = *p); p++) {
+      assert (nvars + 1 <= lit && lit <= nvars + ngroups);
+      printf (" %d", lit - nvars);
+    }
+    printf (" 0\n");
+    fflush (stdout);
+  }
+  msg ("max memory %.1f MB",
+       picosat_max_bytes_allocated (ps) / (double)(1<<20));
+  picosat_reset (ps);
+  msg ("%d reductions", reductions);
+  return res;
+}
diff --git a/test/picosat-965/picomcs.c b/test/picosat-965/picomcs.c
new file mode 100644
index 00000000..3acf7bd7
--- /dev/null
+++ b/test/picosat-965/picomcs.c
@@ -0,0 +1,334 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "picosat.h"
+
+typedef struct Clause { int cid, * lits; struct Clause * next; } Clause;
+typedef struct MCS { int mid, * clauses; struct MCS * next; } MCS;
+
+static int nvars;
+static char * marked;
+
+static Clause * first_clause, * last_clause;
+static int nclauses, first_cid, last_cid;
+
+static MCS * first_mcs, * last_mcs;
+static int nmcs;
+
+static int * stk, szstk, nstk;
+
+static int verbose, join, noprint;
+
+static int lineno = 1, close_input;
+static const char * input_name;
+static FILE * input;
+
+static PicoSAT * ps;
+
+static void release_clauses (void) {
+  Clause * p, * next;
+  for (p = first_clause; p; p = next) {
+    next = p->next;
+    free (p->lits);
+    free (p);
+  }
+}
+
+static void release_mss (void) {
+  MCS * p, * next;
+  for (p = first_mcs; p; p = next) {
+    next = p->next;
+    free (p->clauses);
+    free (p);
+  }
+}
+
+static void release (void) {
+  release_clauses ();
+  release_mss ();
+  free (marked);
+  free (stk);
+}
+
+static void push_stack (int n) {
+  if (nstk == szstk)
+    stk = realloc (stk, (szstk = szstk ? 2*szstk : 1) * sizeof *stk);
+  stk[nstk++] = n;
+}
+
+static void push_clause (void) {
+  Clause * clause;
+  size_t bytes;
+  clause = malloc (sizeof *clause);
+  clause->cid = ++nclauses;
+  clause->next = 0;
+  push_stack (0);
+  bytes = nstk * sizeof *clause->lits;
+  clause->lits = malloc (bytes);
+  memcpy (clause->lits, stk, bytes);
+  if (last_clause) last_clause->next = clause;
+  else first_clause = clause;
+  last_clause = clause;
+  nstk = 0;
+}
+
+static void push_mcs (void) {
+  MCS * mcs;
+  size_t bytes;
+  mcs = malloc (sizeof *mcs);
+  mcs->mid = ++nmcs;
+  mcs->next = 0;
+  push_stack (0);
+  bytes = nstk * sizeof *mcs->clauses;
+  mcs->clauses = malloc (bytes);
+  memcpy (mcs->clauses, stk, bytes);
+  if (last_mcs) last_mcs->next = mcs;
+  else first_mcs = mcs;
+  last_mcs = mcs;
+  nstk = 0;
+}
+
+static int nextch (void) {
+  int res = getc (input);
+  if (res == '\n') lineno++;
+  return res;
+}
+
+static void msg (int level, const char * fmt, ...) {
+  va_list ap;
+  if (level > verbose) return;
+  printf ("c [picomcs] ");
+  va_start (ap, fmt);
+  vprintf (fmt, ap);
+  va_end (ap);
+  fputc ('\n', stdout);
+  fflush (stdout);
+}
+
+static const char * parse (void) {
+  int ch, expclauses, lit, sign;
+  size_t bytes;
+  msg (1, "parsing %s", input_name);
+COMMENTS:
+  ch = nextch ();
+  if (ch == 'c') {
+    while ((ch = nextch ()) != '\n')
+      if (ch == EOF) return "out of file in comment";
+    goto COMMENTS;
+  }
+  if (ch != 'p') 
+INVALID_HEADER:
+    return "invalid header";
+  ungetc (ch, input);
+  if (fscanf (input, "p cnf %d %d", &nvars, &expclauses) != 2)
+    goto INVALID_HEADER;
+  msg (1, "found 'p cnf %d %d' header", nvars, expclauses);
+  bytes = (1 + nvars + expclauses) * sizeof *marked;
+  marked = malloc (bytes);
+  memset (marked, 0, bytes);
+LIT:
+  ch = nextch ();
+  if (ch == ' '  || ch == '\n' || ch == '\t' || ch == '\r') goto LIT;
+  if (ch == EOF) {
+    assert (nclauses <= expclauses);
+    if (nclauses < expclauses) return "clauses missing";
+    return 0;
+  }
+  if (ch == '-') {
+    ch = nextch ();
+    if (!isdigit (ch)) return "expected digit after '-'";
+    if (ch == '0') return "expected positive digit after '-'";
+    sign = -1;
+  } else if (!isdigit (ch)) return "expected '-' or digit";
+  else sign = 1;
+  lit = ch - '0';
+  while (isdigit (ch = nextch ()))
+    lit = 10*lit + (ch - '0');
+  if (lit) {
+    if (lit > nvars) return "maximum variable index exceeded";
+    if (nclauses == expclauses) return "too many clauses";
+    push_stack (sign * lit);
+  } else {
+    assert (nclauses < expclauses);
+    push_clause ();
+  }
+  goto LIT;
+}
+
+#ifndef NDEBUG
+static void dump_clause (Clause * c) {
+  int * p, lit;
+  for (p = c->lits; (lit = *p); p++)
+    printf ("%d ", lit);
+  printf ("0\n");
+}
+
+void dump (void) {
+  Clause * p;
+  printf ("p cnf %d %d\n", nvars, nclauses);
+  for (p = first_clause; p; p = p->next)
+    dump_clause (p);
+}
+#endif
+
+static int clause2selvar (Clause * c) { 
+  int res = c->cid + nvars;
+  assert (first_cid <= res && res <= last_cid);
+  return res;
+}
+
+static void encode_clause (Clause * c) {
+  int * p, lit;
+  if (verbose >= 2) {
+    printf ("c [picomcs] encode clause %d :", c->cid);
+    printf (" %d", -clause2selvar (c));
+    for (p = c->lits; (lit = *p); p++) printf (" %d", lit);
+    fputc ('\n', stdout), fflush (stdout);
+  }
+  picosat_add (ps, -clause2selvar (c));
+  for (p = c->lits; (lit = *p); p++) picosat_add (ps, lit);
+  picosat_add (ps, 0);
+}
+
+static void encode (void) {
+  Clause * p;
+  first_cid = nvars + 1;
+  last_cid = nvars + nclauses;
+  msg (2, "selector variables range %d to %d", first_cid, last_cid);
+  for (p = first_clause; p; p = p->next)
+    encode_clause (p);
+  msg (1, "encoded %d clauses", nclauses);
+}
+
+static void camcs (void) {
+  int cid, i;
+  const int * mcs, * p;
+  msg (1, "starting to compute all minimal correcting sets");
+  while ((mcs = picosat_next_minimal_correcting_subset_of_assumptions (ps))) {
+    for (p = mcs; (cid = *p); p++)
+      push_stack (cid);
+    if (verbose >= 2) {
+      printf ("c [picomcs] mcs %d :", nmcs);
+      for (i = 0; i < nstk; i++) printf (" %d", stk[i] - nvars);
+      fputc ('\n', stdout);
+      fflush (stdout);
+    } else if (verbose && isatty (1)) {
+      printf ("\rc [picomcs] mcs %d", nmcs);
+      fflush (stdout);
+    }
+    push_mcs ();
+  }
+  if (verbose && isatty (1)) fputc ('\r', stdout);
+  msg (1, "found %d minimal correcting sets", nmcs);
+}
+
+static void cumcscb (void * state, int nmcs, int nhumus) {
+  int * ptr = state;
+  *ptr = nmcs;
+  ptr[0] = nmcs, ptr[1] = nhumus;
+  if (!verbose || (!isatty (1) && verbose == 1)) return;
+  if (verbose == 1) fputc ('\r', stdout);
+  printf ("c [picomcs] mcs %d humus %d", nmcs, nhumus);
+  if (verbose >= 2) fputc ('\n', stdout);
+  fflush (stdout);
+}
+
+static void cumcs (void) {
+  int stats[2], count, cid;
+  const int * humus, * p;
+  stats[0] = stats[1] = 0;
+  humus = picosat_humus (ps, cumcscb, stats);
+  if (isatty (1) && verbose == 1) fputc ('\n', stdout);
+  count = 0;
+  for (p = humus; (cid = *p); p++) {
+    if (marked[cid]) continue;
+    marked[cid] = 1;
+    count++;
+  }
+  assert (count == stats[1]);
+  msg (1, 
+    "computed union of minimal correcting sets of size %d with %d mcs", 
+    stats[1], stats[0]);
+}
+
+static void
+print_umcs (void) {
+  int cid;
+  printf ("v");
+  for (cid = first_cid; cid <= last_cid; cid++)
+    if (marked[cid])
+      printf (" %d", cid - nvars);
+  printf (" 0\n");
+}
+
+static void
+print_mcs (MCS * mcs) 
+{
+  const int * p;
+  int cid;
+  printf ("v");
+  for (p = mcs->clauses; (cid = *p); p++)
+    printf (" %d", cid - nvars);
+  printf (" 0\n");
+}
+
+static void
+print_all_mcs (void)
+{
+  MCS * p;
+  for (p = first_mcs; p; p = p->next)
+    print_mcs (p);
+}
+
+int main (int argc, char ** argv) {
+  const char * perr;
+  int i, res;
+  for (i = 1; i < argc; i++) {
+    if (!strcmp (argv[i], "-h")) {
+      printf ("usage: picomcs [-h][-v][-j][-n][<input>]\n");
+      exit (0);
+    }
+    else if (!strcmp (argv[i], "-v")) verbose++;
+    else if (!strcmp (argv[i], "-j")) join = 1;
+    else if (!strcmp (argv[i], "-n")) noprint = 1;
+    else if (argv[i][0] == '-') {
+      fprintf (stderr, "*** picomcs: invalid option '%s'\n", argv[i]);
+      exit (1);
+    } else if (input_name) {
+      fprintf (stderr, "*** picomcs: two input files specified\n");
+      exit (1);
+    } else if (!(input = fopen ((input_name = argv[i]), "r"))) {
+      fprintf (stderr, "*** picomcs: can not read '%s'\n", argv[i]);
+      exit (1);
+    } else close_input = 1;
+  }
+  if (!input_name) input_name = "<stdin>", input = stdin;
+  if ((perr = parse ())) {
+    fprintf (stderr, "%s:%d: parse error: %s\n", input_name, lineno, perr);
+    exit (1);
+  }
+  if (close_input) fclose (input);
+  ps = picosat_init ();
+  picosat_set_prefix (ps, "c [picosat] ");
+  encode ();
+  for (i = first_cid; i <= last_cid; i++) 
+    picosat_set_default_phase_lit (ps, i, 1);
+  for (i = first_cid; i <= last_cid; i++) picosat_assume (ps, i);
+  res = picosat_sat (ps, -1);
+  if (res == 10) printf ("s SATISFIABLE\n");
+  else printf ("s UNSATISFIABLE\n");
+  fflush (stdout);
+  if (join) cumcs (); else camcs ();
+  if (verbose) picosat_stats (ps);
+  picosat_reset (ps);
+  if (!noprint) {
+    if (join) print_umcs (); else print_all_mcs ();
+  }
+  release ();
+  return res;
+}
diff --git a/test/picosat-965/picomus.c b/test/picosat-965/picomus.c
new file mode 100644
index 00000000..f92a2d58
--- /dev/null
+++ b/test/picosat-965/picomus.c
@@ -0,0 +1,407 @@
+/****************************************************************************
+Copyright (c) 2011-2014, Armin Biere, Johannes Kepler University.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+****************************************************************************/
+
+#include "picosat.h"
+
+#include <stdio.h>
+#include <assert.h>
+#include <string.h>
+#include <stdarg.h>
+#include <ctype.h>
+
+#define MAXNONREDROUNDS 3
+#define MINCOREROUNDS 5
+#define MAXCOREROUNDS 100
+
+typedef struct Cls { int lit, red, * lits; } Cls;
+
+static int verbose, nowitness;
+static int fclose_input, pclose_input, close_output;
+static FILE * input_file, * output_file;
+static const char * input_name, * output_name;
+static int lineno = 1;
+static int nvars, nclauses;
+static Cls * clauses;
+static int * lits, nlits, szlits;
+static double start;
+static int reductions;
+
+static PicoSAT * ps;
+
+static int next (void) {
+  int res = fgetc (input_file);
+  if (res == '\n') lineno++;
+  return res;
+}
+
+static void msg (int level, const char * fmt, ...) {
+  va_list ap;
+  if (verbose < level) return;
+  fputs ("c [picomus] ", stdout);
+  va_start (ap, fmt);
+  vfprintf (stdout, fmt, ap);
+  va_end (ap);
+  fputc ('\n', stdout);
+  fflush (stdout);
+}
+
+static void warn (const char * fmt, ...) {
+  va_list ap;
+  if (verbose < 0) return;
+  fputs ("c [picomus] WARNING: ", stdout);
+  va_start (ap, fmt);
+  vfprintf (stdout, fmt, ap);
+  va_end (ap);
+  fputc ('\n', stdout);
+  fflush (stdout);
+}
+
+static const char * parse (void) {
+  int ch, n, lit, sign, i;
+  Cls * c;
+HEADER:
+  ch = next ();
+  if (ch == 'c') {
+    while ((ch = next ()) != '\n')
+      if (ch == EOF) return "EOF after 'c'";
+    goto HEADER;
+  }
+  if (ch == '\r') goto HEADER;
+  if (ch != 'p') return "expected 'c' or 'p'";
+  if (fscanf (input_file, " cnf %d %d", &nvars, &nclauses) != 2)
+    return "invalid header";
+  msg (1, "p cnf %d %d", nvars, nclauses);
+  clauses = calloc (nclauses, sizeof *clauses);
+  lit = n = 0;
+LIT:
+  ch = next ();
+  if (ch == ' ' || ch == '\n' || ch == '\t' || ch == '\r') goto LIT;
+  if (ch == 'c') {
+    while ((ch = next ()) != '\n')
+      if (ch == EOF) return "EOF after 'c'";
+    goto LIT;
+  }
+  if (ch == EOF) {
+    if (lit) return "zero missing";
+    if (n < nclauses) return "clauses missing";
+    return 0;
+  }
+  if (n == nclauses) return "too many clauses";
+  if (ch == '-') {
+    sign = -1;
+    ch = next ();
+    if (!isdigit (ch)) return "expected digit after '-'";
+  } else sign = 1;
+  if (!isdigit (ch)) return "expected digit";
+  lit = ch - '0';
+  while (isdigit (ch = next ()))
+    lit = 10 * lit + (ch - '0');
+  if (lit > nvars) return "maximum variable index exceeded";
+  if (lit) {
+    lit *= sign;
+    if (nlits == szlits) {
+      szlits = szlits ? 2 * szlits : 1;
+      lits = realloc (lits, szlits * sizeof *lits);
+    }
+    lits[nlits++] = lit;
+  } else {
+    c = clauses + n++;
+    c->lits = malloc ((nlits + 1) * sizeof *c->lits);
+    for (i = 0; i < nlits; i++)
+      c->lits[i] = lits[i];
+    c->lits[i] = 0;
+    nlits = 0;
+  }
+  goto LIT;
+}
+
+static void die (const char * fmt, ...) {
+  va_list ap;
+  fputs ("*** picomus: ", stdout);
+  va_start (ap, fmt);
+  vfprintf (stdout, fmt, ap);
+  va_end (ap);
+  fputc ('\n', stdout);
+  fflush (stdout);
+  exit (1);
+}
+
+static double percent (double a, double b) { return b?100.0*a/b:0.0; }
+
+static void callback (void * dummy, const int * mus) {
+  int remaining;
+  const int * p;
+  (void) dummy;
+  if (verbose <= 0) return;
+  remaining = 0;
+  for (p = mus; *p; p++) remaining++;
+  assert (remaining <= nclauses);
+  reductions++;
+  msg (1, "reduction %d to %d = %.0f%% out of %d after %.1f sec",
+       reductions,
+       remaining, percent (remaining, nclauses), nclauses,
+       picosat_time_stamp () - start);
+}
+
+static const char * USAGE =
+"picomus [-h][-v][-q] [ <input> [ <output> ] ]\n"
+"\n"
+"  -h  print this command line option summary\n"
+"  -v  increase verbosity level (default 0 = no messages)\n"
+"  -q  be quiet (no warnings nor messages)\n"
+"\n"
+"This tool is a SAT solver that uses the PicoSAT library to\n"
+"generate a 'minimal unsatisfiable core' also known as 'minimal\n"
+"unsatisfiable set' (MUS) of a CNF in DIMACS format.\n"
+"\n"
+"Both file arguments can be \"-\" and then denote <stdin> and\n"
+"<stdout> respectively.  If no input file is given <stdin> is used.\n"
+"If no output file is specified the MUS is computed and only printed\n"
+"to <stdout> in the format of the SAT competition 2011 MUS track.\n"
+"\n"
+"Note, that the 's ...' lines and in case the instance is satisfiable\n"
+"also the 'v ...' lines for the satisfying assignment are always\n"
+"printed to <stdout> (or not printed at all with '-q').\n"
+"\n"
+"If '-n' is specified satisfying assignment and MUS printing\n"
+"on <stdout> (using the 'v ...' format) is suppressed.\n"
+"The 's ...' line is still printed unless '-q' is specified.\n"
+"If <output> is specified an MUS is written to this file,\n"
+"even if '-n' or '-q' is used.\n"
+"\n"
+#ifndef TRACE
+"WARNING: PicosSAT is compiled without trace support.\n"
+"\n"
+"This typically slows down this MUS extractor, since\n"
+"it only relies on clause selector variables and\n"
+"can not make use of core extraction.  To enable\n"
+"trace generation use './configure.sh --trace' or\n"
+"'./configure.sh -O --trace' when building PicoSAT.\n"
+#else
+"Since trace generation code is included, this binary\n"
+"uses also core extraction in addition to clause selector\n"
+"variables.\n"
+#endif
+;
+
+int main (int argc, char ** argv) {
+  int i, * p, n, oldn, red, nonred, res, round, printed, len;
+  const char * err;
+  const int * q;
+  char * cmd;
+  Cls * c;
+#ifndef NDEBUG
+  int tmp;
+#endif
+  start = picosat_time_stamp ();
+  for (i = 1; i < argc; i++) {
+    if (!strcmp (argv[i], "-h")) {
+      fputs (USAGE, stdout);
+      exit (0);
+    } else if (!strcmp (argv[i], "-v")) {
+      if (verbose < 0) die ("'-v' option after '-q'");
+      verbose++;
+    } else if (!strcmp (argv[i], "-q")) {
+      if (verbose < 0) die ("two '-q' options");
+      if (verbose > 0) die ("'-q' option after '-v'");
+      verbose = -1;
+    } else if (!strcmp (argv[i], "-n")) nowitness = 1;
+    else if (argv[i][0] == '-' && argv[i][1]) 
+      die ("invalid command line option '%s'", argv[i]);
+    else if (output_name) die ("too many arguments");
+    else if (!input_name) input_name = argv[i];
+    else output_name = argv[i];
+  }
+  if (!output_name) warn ("no output file given");
+  if (input_name && strcmp (input_name, "-")) {
+    len = strlen (input_name);
+    if (len >= 3 && !strcmp (input_name + len - 3, ".gz")) {
+      cmd = malloc (len + 20);
+      sprintf (cmd, "gunzip -c %s 2>/dev/null", input_name);
+      input_file = popen (cmd, "r");
+      pclose_input = 1;
+      free (cmd);
+    } else input_file = fopen (input_name, "r"), fclose_input = 1;
+    if (!input_file) die ("can not read '%s'", input_name);
+  } else input_file = stdin, input_name = "-";
+  if ((err =  parse ())) {
+    fprintf (stdout, "%s:%d: %s\n", input_name, lineno, err);
+    fflush (stdout);
+    exit (1);
+  }
+  if (fclose_input) fclose (input_file);
+  if (pclose_input) pclose (input_file);
+  ps = picosat_init ();
+  picosat_set_prefix (ps, "c [picosat] ");
+  picosat_set_output (ps, stdout);
+  if (verbose > 1) picosat_set_verbosity (ps, verbose - 1);
+  printed = 0;
+  if (!picosat_enable_trace_generation (ps))
+    warn ("PicoSAT compiled without trace generation"),
+    warn ("core extraction disabled");
+  else {
+    n = nclauses;
+    nonred = 0;
+    for (round = 1; round <= MAXCOREROUNDS; round++) {
+      if (verbose > 1)
+	msg (1, "starting core extraction round %d", round);
+      picosat_set_seed (ps, round);
+      for (i = 0; i < nclauses; i++) {
+	c = clauses + i;
+	if (c->red) {
+	  picosat_add (ps, 1);
+	  picosat_add (ps, -1);
+	} else {
+	  for (p = c->lits; *p; p++)
+	    picosat_add (ps, *p);
+	}
+#ifndef NDEBUG
+	tmp = 
+#endif
+	picosat_add (ps, 0);
+	assert (tmp == i);
+      }
+      res = picosat_sat (ps, -1);
+      if (res == 10) { assert (round == 1); goto SAT; }
+      assert (res == 20);
+      if (!printed) {
+	assert (round == 1);
+	printed = 1;
+	if (verbose >= 0)
+	  printf ("s UNSATISFIABLE\n"),
+	  fflush (stdout);
+      }
+      for (i = 0; i < nclauses; i++) {
+	c = clauses + i;
+	if (c->red) { assert (!picosat_coreclause (ps, i)); continue; }
+	if (picosat_coreclause (ps, i)) continue;
+	c->red = 1;
+      }
+      oldn = n;
+      n = 0;
+      for (i = 0; i < nclauses; i++) if (!clauses[i].red) n++;
+      msg (1, "extracted core %d of size %d = %0.f%% out of %d after %.1f sec",
+	   round, n, percent (n, nclauses), nclauses,
+	   picosat_time_stamp () - start);
+      assert (oldn >= n);
+      picosat_reset (ps);
+      ps = picosat_init ();
+      picosat_set_prefix (ps, "c [picosat] ");
+      picosat_set_output (ps, stdout);
+      if (round >= MINCOREROUNDS) {
+	red = oldn - n;
+	if (red < 10 && (100*red + 99)/oldn < 2) {
+	  nonred++;
+	  if (nonred > MAXNONREDROUNDS) break;
+	}
+      }
+      if (round < MAXCOREROUNDS) picosat_enable_trace_generation (ps);
+    }
+  }
+  for (i = 0; i < nclauses; i++) {
+    c = clauses + i;
+    if (c->red) {
+      picosat_add (ps, 1);
+      picosat_add (ps, -1);
+#ifndef NDEBUG
+      tmp = 
+#endif
+      picosat_add (ps, 0);
+      assert (tmp == i);
+      continue;
+    }
+    c->lit = nvars + i + 1;
+    picosat_add (ps, -c->lit);
+    for (p = c->lits; *p; p++)
+      (void) picosat_add (ps, *p);
+#ifndef NDEBUG
+    tmp = 
+#endif
+    picosat_add (ps, 0);
+    assert (tmp == i);
+  }
+  for (i = 0; i < nclauses; i++) {
+    c = clauses + i;
+    if (c->red) continue;
+    picosat_assume (ps, c->lit);
+  }
+  res = picosat_sat (ps, -1);
+  if (res == 20) {
+    if (!printed && verbose >= 0)
+      printf ("s UNSATISFIABLE\n"), fflush (stdout);
+    for (i = 0; i < nclauses; i++) clauses[i].red = 1;
+    q = picosat_mus_assumptions (ps, 0, callback, 1);
+    while ((i = *q++)) {
+      i -= nvars + 1;
+      assert (0 <= i && i < nclauses);
+      clauses[i].red = 0;
+    }
+  } else {
+SAT:
+    assert (res == 10);
+    if (!printed && verbose >= 0)
+      printf ("s SATISFIABLE\n"), fflush (stdout);
+    if (!nowitness && verbose >= 0) {
+      for (i = 1; i <= nvars; i++)
+	printf ("v %d\n", ((picosat_deref (ps, i) < 0) ? -1 : 1) * i);
+      printf ("v 0\n");
+    }
+  }
+  if (verbose > 0) picosat_stats (ps);
+  picosat_reset (ps);
+  n = 0;
+  for (i = 0; i < nclauses; i++) if (!clauses[i].red) n++;
+  red = nclauses - n;
+  msg (1, "found %d redundant clauses %.0f%%", red, percent (red, nclauses));
+  if (res == 20)
+    msg (0, "computed MUS of size %d out of %d (%.0f%%)",
+	 n, nclauses, percent (n, nclauses));
+  if (output_name && strcmp (output_name, "-")) {
+    output_file = fopen (output_name, "w");
+    if (!output_file) die ("can not write '%s'", output_name);
+    close_output = 1;
+  } else if (output_name && !strcmp (output_name, "-")) output_file = stdout;
+  if (output_file) {
+    fprintf (output_file, "p cnf %d %d\n", nvars, n);
+    for (i = 0; i < nclauses; i++) 
+      if (!clauses[i].red) {
+	for (p = clauses[i].lits; *p; p++) fprintf (output_file, "%d ", *p);
+	fprintf (output_file, "0\n");
+      }
+    if (close_output) fclose (output_file);
+  } 
+  if (res == 20) {
+    if (!nowitness && verbose >= 0) {
+      for (i = 0; i < nclauses; i++)
+	if (!clauses[i].red) printf ("v %d\n", i+1);
+      printf ("v 0\n");
+    }
+  }
+  msg (1, "%s %d irredundant clauses %.0f%%",
+       output_file ? "printed" : "computed", n, percent (n, nclauses));
+  for (i = 0; i < nclauses; i++) free (clauses[i].lits);
+  free (clauses);
+  free (lits);
+  msg (1, "%d reductions in %.1f seconds", 
+       reductions, picosat_time_stamp () - start);
+  return res;
+}
diff --git a/test/picosat-965/picosat.c b/test/picosat-965/picosat.c
new file mode 100644
index 00000000..76db7ae0
--- /dev/null
+++ b/test/picosat-965/picosat.c
@@ -0,0 +1,8502 @@
+/****************************************************************************
+Copyright (c) 2006 - 2015, Armin Biere, Johannes Kepler University.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+****************************************************************************/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <limits.h>
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdint.h>
+
+#include "picosat.h"
+
+/* By default code for 'all different constraints' is disabled, since 'NADC'
+ * is defined.
+ */
+#define NADC
+
+/* By default we enable failed literals, since 'NFL' is undefined.
+ *
+#define NFL
+ */
+
+/* By default we 'detach satisfied (large) clauses', e.g. NDSC undefined.
+ *
+#define NDSC
+ */
+
+/* Do not use luby restart schedule instead of inner/outer.
+ *
+#define NLUBY
+ */
+
+/* Enabling this define, will use gnuplot to visualize how the scores evolve.
+ *
+#define VISCORES 
+ */
+#ifdef VISCORES
+// #define WRITEGIF		/* ... to generate a video */
+#endif
+
+#ifdef VISCORES
+#ifndef WRITEGIF
+#include <unistd.h>		/* for 'usleep' */
+#endif
+#endif
+
+#ifdef RCODE
+#include <R.h>
+#endif
+
+#define MINRESTART	100	/* minimum restart interval */
+#define MAXRESTART	1000000 /* maximum restart interval */
+#define RDECIDE		1000	/* interval of random decisions */
+#define FRESTART	110	/* restart increase factor in percent */
+#define FREDUCE		110	/* reduce increase factor in percent  */
+#define FREDADJ		121	/* reduce increase adjustment factor */
+#define MAXCILS		10	/* maximal number of unrecycled internals */
+#define FFLIPPED	10000	/* flipped reduce factor */
+#define FFLIPPEDPREC	10000000/* flipped reduce factor precision */
+#define INTERRUPTLIM	1024	/* check interrupt after that many decisions */
+
+#ifndef TRACE
+#define NO_BINARY_CLAUSES	/* store binary clauses more compactly */
+#endif
+
+/* For debugging purposes you may want to define 'LOGGING', which actually
+ * can be enforced by using './configure.sh --log'.
+ */
+#ifdef LOGGING
+#define LOG(code) do { code; } while (0)
+#else
+#define LOG(code) do { } while (0)
+#endif
+#define NOLOG(code) do { } while (0)		/* log exception */
+#define ONLYLOG(code) do { code; } while (0)	/* force logging */
+
+#define FALSE ((Val)-1)
+#define UNDEF ((Val)0)
+#define TRUE ((Val)1)
+
+#define COMPACT_TRACECHECK_TRACE_FMT 0
+#define EXTENDED_TRACECHECK_TRACE_FMT 1
+#define RUP_TRACE_FMT 2
+
+#define NEWN(p,n) do { (p) = new (ps, sizeof (*(p)) * (n)); } while (0)
+#define CLRN(p,n) do { memset ((p), 0, sizeof (*(p)) * (n)); } while (0)
+#define CLR(p) CLRN(p,1)
+#define DELETEN(p,n) \
+  do { delete (ps, p, sizeof (*(p)) * (n)); (p) = 0; } while (0)
+
+#define RESIZEN(p,old_num,new_num) \
+  do { \
+    size_t old_size = sizeof (*(p)) * (old_num); \
+    size_t new_size = sizeof (*(p)) * (new_num); \
+    (p) = resize (ps, (p), old_size, new_size) ; \
+  } while (0)
+
+#define ENLARGE(start,head,end) \
+  do { \
+    unsigned old_num = (ptrdiff_t)((end) - (start)); \
+    size_t new_num = old_num ? (2 * old_num) : 1; \
+    unsigned count = (head) - (start); \
+    assert ((start) <= (end)); \
+    RESIZEN((start),old_num,new_num); \
+    (head) = (start) + count; \
+    (end) = (start) + new_num; \
+  } while (0)
+
+#define NOTLIT(l) (ps->lits + (1 ^ ((l) - ps->lits)))
+
+#define LIT2IDX(l) ((ptrdiff_t)((l) - ps->lits) / 2)
+#define LIT2IMPLS(l) (ps->impls + (ptrdiff_t)((l) - ps->lits))
+#define LIT2INT(l) ((int)(LIT2SGN(l) * LIT2IDX(l)))
+#define LIT2SGN(l) (((ptrdiff_t)((l) - ps->lits) & 1) ? -1 : 1)
+#define LIT2VAR(l) (ps->vars + LIT2IDX(l))
+#define LIT2HTPS(l) (ps->htps + (ptrdiff_t)((l) - ps->lits))
+#define LIT2JWH(l) (ps->jwh + ((l) - ps->lits))
+
+#ifndef NDSC
+#define LIT2DHTPS(l) (ps->dhtps + (ptrdiff_t)((l) - ps->lits))
+#endif
+
+#ifdef NO_BINARY_CLAUSES
+typedef uintptr_t Wrd;
+#define ISLITREASON(C) (1&(Wrd)C)
+#define LIT2REASON(L) \
+  (assert (L->val==TRUE), ((Cls*)(1 + (2*(L - ps->lits)))))
+#define REASON2LIT(C) ((Lit*)(ps->lits + ((Wrd)C)/2))
+#endif
+
+#define ENDOFCLS(c) ((void*)((Lit**)(c)->lits + (c)->size))
+
+#define SOC ((ps->oclauses == ps->ohead) ? ps->lclauses : ps->oclauses)
+#define EOC (ps->lhead)
+#define NXC(p) (((p) + 1 == ps->ohead) ? ps->lclauses : (p) + 1)
+
+#define OIDX2IDX(idx) (2 * ((idx) + 1))
+#define LIDX2IDX(idx) (2 * (idx) + 1)
+
+#define ISLIDX(idx) ((idx)&1)
+
+#define IDX2OIDX(idx) (assert(!ISLIDX(idx)), (idx)/2 - 1)
+#define IDX2LIDX(idx) (assert(ISLIDX(idx)), (idx)/2)
+
+#define EXPORTIDX(idx) \
+  ((ISLIDX(idx) ? (IDX2LIDX (idx) + (ps->ohead - ps->oclauses)) : IDX2OIDX(idx)) + 1)
+
+#define IDX2CLS(i) \
+  (assert(i), (ISLIDX(i) ? ps->lclauses : ps->oclauses)[(i)/2 - !ISLIDX(i)])
+
+#define IDX2ZHN(i) (assert(i), (ISLIDX(i) ? ps->zhains[(i)/2] : 0))
+
+#define CLS2TRD(c) (((Trd*)(c)) - 1)
+#define CLS2IDX(c) ((((Trd*)(c)) - 1)->idx)
+
+#define CLS2ACT(c) \
+  ((Act*)((assert((c)->learned)),assert((c)->size>2),ENDOFCLS(c)))
+
+#define VAR2LIT(v) (ps->lits + 2 * ((v) - ps->vars))
+#define VAR2RNK(v) (ps->rnks + ((v) - ps->vars))
+
+#define RNK2LIT(r) (ps->lits + 2 * ((r) - ps->rnks))
+#define RNK2VAR(r) (ps->vars + ((r) - ps->rnks))
+
+#define BLK_FILL_BYTES 8
+#define SIZE_OF_BLK (sizeof (Blk) - BLK_FILL_BYTES)
+
+#define PTR2BLK(void_ptr) \
+  ((void_ptr) ? (Blk*)(((char*)(void_ptr)) - SIZE_OF_BLK) : 0)
+
+#define AVERAGE(a,b) ((b) ? (((double)a) / (double)(b)) : 0.0)
+#define PERCENT(a,b) (100.0 * AVERAGE(a,b))
+
+#ifndef RCODE
+#define ABORT(msg) \
+  do { \
+    fputs ("*** picosat: " msg "\n", stderr); \
+    abort (); \
+  } while (0)
+#else
+#define ABORT(msg) \
+  do { \
+    Rf_error (msg); \
+  } while (0)
+#endif
+
+#define ABORTIF(cond,msg) \
+  do { \
+    if (!(cond)) break; \
+    ABORT (msg); \
+  } while (0)
+
+#define ZEROFLT		(0x00000000u)
+#define EPSFLT		(0x00000001u)
+#define INFFLT		(0xffffffffu)
+
+#define FLTCARRY	(1u << 25)
+#define FLTMSB		(1u << 24)
+#define FLTMAXMANTISSA	(FLTMSB - 1)
+
+#define FLTMANTISSA(d)	((d) & FLTMAXMANTISSA)
+#define FLTEXPONENT(d)	((int)((d) >> 24) - 128)
+
+#define FLTMINEXPONENT	(-128)
+#define FLTMAXEXPONENT	(127)
+
+#define CMPSWAPFLT(a,b) \
+  do { \
+    Flt tmp; \
+    if (((a) < (b))) \
+      { \
+	tmp = (a); \
+	(a) = (b); \
+	(b) = tmp; \
+      } \
+  } while (0)
+
+#define UNPACKFLT(u,m,e) \
+  do { \
+    (m) = FLTMANTISSA(u); \
+    (e) = FLTEXPONENT(u); \
+    (m) |= FLTMSB; \
+  } while (0)
+
+#define INSERTION_SORT_LIMIT 10
+
+#define SORTING_SWAP(T,p,q) \
+do { \
+  T tmp = *(q); \
+  *(q) = *(p); \
+  *(p) = tmp; \
+} while (0)
+
+#define SORTING_CMP_SWAP(T,cmp,p,q) \
+do { \
+  if ((cmp) (ps, *(p), *(q)) > 0) \
+    SORTING_SWAP (T, p, q); \
+} while(0)
+
+#define QUICKSORT_PARTITION(T,cmp,a,l,r) \
+do { \
+  T pivot; \
+  int j; \
+  i = (l) - 1; 			/* result in 'i' */ \
+  j = (r); \
+  pivot = (a)[j]; \
+  for (;;) \
+    { \
+      while ((cmp) (ps, (a)[++i], pivot) < 0) \
+	; \
+      while ((cmp) (ps, pivot, (a)[--j]) < 0) \
+        if (j == (l)) \
+	  break; \
+      if (i >= j) \
+	break; \
+      SORTING_SWAP (T, (a) + i, (a) + j); \
+    } \
+  SORTING_SWAP (T, (a) + i, (a) + (r)); \
+} while(0)
+
+#define QUICKSORT(T,cmp,a,n) \
+do { \
+  int l = 0, r = (n) - 1, m, ll, rr, i; \
+  assert (ps->ihead == ps->indices); \
+  if (r - l <= INSERTION_SORT_LIMIT) \
+    break; \
+  for (;;) \
+    { \
+      m = (l + r) / 2; \
+      SORTING_SWAP (T, (a) + m, (a) + r - 1); \
+      SORTING_CMP_SWAP (T, cmp, (a) + l, (a) + r - 1); \
+      SORTING_CMP_SWAP (T, cmp, (a) + l, (a) + r); \
+      SORTING_CMP_SWAP (T, cmp, (a) + r - 1, (a) + r); \
+      QUICKSORT_PARTITION (T, cmp, (a), l + 1, r - 1); \
+      if (i - l < r - i) \
+	{ \
+	  ll = i + 1; \
+	  rr = r; \
+	  r = i - 1; \
+	} \
+      else \
+	{ \
+	  ll = l; \
+	  rr = i - 1; \
+	  l = i + 1; \
+	} \
+      if (r - l > INSERTION_SORT_LIMIT) \
+	{ \
+	  assert (rr - ll > INSERTION_SORT_LIMIT); \
+	  if (ps->ihead == ps->eoi) \
+	    ENLARGE (ps->indices, ps->ihead, ps->eoi); \
+	  *ps->ihead++ = ll; \
+	  if (ps->ihead == ps->eoi) \
+	    ENLARGE (ps->indices, ps->ihead, ps->eoi); \
+	  *ps->ihead++ = rr; \
+	} \
+      else if (rr - ll > INSERTION_SORT_LIMIT) \
+        { \
+	  l = ll; \
+	  r = rr; \
+	} \
+      else if (ps->ihead > ps->indices) \
+	{ \
+	  r = *--ps->ihead; \
+	  l = *--ps->ihead; \
+	} \
+      else \
+	break; \
+    } \
+} while (0)
+
+#define INSERTION_SORT(T,cmp,a,n) \
+do { \
+  T pivot; \
+  int l = 0, r = (n) - 1, i, j; \
+  for (i = r; i > l; i--) \
+    SORTING_CMP_SWAP (T, cmp, (a) + i - 1, (a) + i); \
+  for (i = l + 2; i <= r; i++)  \
+    { \
+      j = i; \
+      pivot = (a)[i]; \
+      while ((cmp) (ps, pivot, (a)[j - 1]) < 0) \
+        { \
+	  (a)[j] = (a)[j - 1]; \
+	  j--; \
+	} \
+      (a)[j] = pivot; \
+    } \
+} while (0)
+
+#ifdef NDEBUG
+#define CHECK_SORTED(cmp,a,n) do { } while(0)
+#else
+#define CHECK_SORTED(cmp,a,n) \
+do { \
+  int i; \
+  for (i = 0; i < (n) - 1; i++) \
+    assert ((cmp) (ps, (a)[i], (a)[i + 1]) <= 0); \
+} while(0)
+#endif
+
+#define SORT(T,cmp,a,n) \
+do { \
+  T * aa = (a); \
+  int nn = (n); \
+  QUICKSORT (T, cmp, aa, nn); \
+  INSERTION_SORT (T, cmp, aa, nn); \
+  assert (ps->ihead == ps->indices); \
+  CHECK_SORTED (cmp, aa, nn); \
+} while (0)
+
+#define WRDSZ (sizeof (long) * 8)
+
+#ifdef RCODE
+#define fprintf(...) do { } while (0)
+#define vfprintf(...) do { } while (0)
+#define fputs(...) do { } while (0)
+#define fputc(...) do { } while (0)
+#endif
+
+typedef unsigned Flt;		/* 32 bit deterministic soft float */
+typedef Flt Act;		/* clause and variable activity */
+typedef struct Blk Blk;		/* allocated memory block */
+typedef struct Cls Cls;		/* clause */
+typedef struct Lit Lit;		/* literal */
+typedef struct Rnk Rnk;		/* variable to score mapping */
+typedef signed char Val;	/* TRUE, UNDEF, FALSE */
+typedef struct Var Var;		/* variable */
+#ifdef TRACE
+typedef struct Trd Trd;		/* trace data for clauses */
+typedef struct Zhn Zhn;		/* compressed chain (=zain) data */
+typedef unsigned char Znt;	/* compressed antecedent data */
+#endif
+
+#ifdef NO_BINARY_CLAUSES
+typedef struct Ltk Ltk;
+
+struct Ltk
+{
+  Lit ** start;
+  unsigned count : WRDSZ == 32 ? 27 : 32;
+  unsigned ldsize : WRDSZ == 32 ? 5 : 32;
+};
+#endif
+
+struct Lit
+{
+  Val val;
+};
+
+struct Var
+{
+  unsigned mark		: 1;	/*bit 1*/
+  unsigned resolved	: 1;	/*bit 2*/
+  unsigned phase	: 1;	/*bit 3*/
+  unsigned assigned	: 1;	/*bit 4*/
+  unsigned used		: 1;	/*bit 5*/
+  unsigned failed	: 1;	/*bit 6*/
+  unsigned internal	: 1;	/*bit 7*/
+  unsigned usedefphase  : 1;    /*bit 8*/
+  unsigned defphase     : 1;    /*bit 9*/
+  unsigned msspos       : 1;    /*bit 10*/
+  unsigned mssneg       : 1;    /*bit 11*/
+  unsigned humuspos     : 1;    /*bit 12*/
+  unsigned humusneg     : 1;    /*bit 13*/
+  unsigned partial      : 1;    /*bit 14*/
+#ifdef TRACE
+  unsigned core		: 1;	/*bit 15*/
+#endif
+  unsigned level;
+  Cls *reason;
+#ifndef NADC
+  Lit ** inado;
+  Lit ** ado;
+  Lit *** adotabpos;
+#endif
+};
+
+struct Rnk
+{
+  Act score;
+  unsigned pos : 30;			/* 0 iff not on heap */
+  unsigned moreimportant : 1;
+  unsigned lessimportant : 1;
+};
+
+struct Cls
+{
+  unsigned size;
+
+  unsigned collect:1;	/* bit 1 */
+  unsigned learned:1;	/* bit 2 */
+  unsigned locked:1;	/* bit 3 */
+  unsigned used:1;	/* bit 4 */
+#ifndef NDEBUG
+  unsigned connected:1;	/* bit 5 */
+#endif
+#ifdef TRACE
+  unsigned collected:1;	/* bit 6 */
+  unsigned core:1;	/* bit 7 */
+#endif
+
+#define LDMAXGLUE 25	/* 32 - 7 */
+#define MAXGLUE 	((1<<LDMAXGLUE)-1)
+
+  unsigned glue:LDMAXGLUE;
+
+  Cls *next[2];
+  Lit *lits[2];
+};
+
+#ifdef TRACE
+struct Zhn
+{
+  unsigned ref:31;
+  unsigned core:1;
+  Znt * liz;
+  Znt znt[0];
+};
+
+struct Trd
+{
+  unsigned idx;
+  Cls cls[0];
+};
+#endif
+
+struct Blk
+{
+#ifndef NDEBUG
+  union
+  {
+    size_t size;		/* this is what we really use */
+    void *as_two_ptrs[2];	/* 2 * sizeof (void*) alignment of data */
+  }
+  header;
+#endif
+  char data[BLK_FILL_BYTES];
+};
+
+enum State
+{
+  RESET = 0,
+  READY = 1,
+  SAT = 2,
+  UNSAT = 3,
+  UNKNOWN = 4,
+};
+
+enum Phase
+{
+  POSPHASE,
+  NEGPHASE,
+  JWLPHASE,
+  RNDPHASE,
+};
+
+struct PicoSAT 
+{
+  enum State state;
+  enum Phase defaultphase;
+  int last_sat_call_result;
+
+  FILE *out;
+  char * prefix;
+  int verbosity;
+  int plain;
+  unsigned LEVEL;
+  unsigned max_var;
+  unsigned size_vars;
+
+  Lit *lits;
+  Var *vars;
+  Rnk *rnks;
+  Flt *jwh;
+  Cls **htps;
+#ifndef NDSC
+  Cls **dhtps;
+#endif
+#ifdef NO_BINARY_CLAUSES
+  Ltk *impls;
+  Cls impl, cimpl;
+  int implvalid, cimplvalid;
+#else
+  Cls **impls;
+#endif
+  Lit **trail, **thead, **eot, **ttail, ** ttail2;
+#ifndef NADC
+  Lit **ttailado;
+#endif
+  unsigned adecidelevel;
+  Lit **als, **alshead, **alstail, **eoals;
+  Lit **CLS, **clshead, **eocls;
+  int *rils, *rilshead, *eorils;
+  int *cils, *cilshead, *eocils;
+  int *fals, *falshead, *eofals;
+  int *mass, szmass;
+  int *mssass, szmssass;
+  int *mcsass, nmcsass, szmcsass;
+  int *humus, szhumus;
+  Lit *failed_assumption;
+  int extracted_all_failed_assumptions;
+  Rnk **heap, **hhead, **eoh;
+  Cls **oclauses, **ohead, **eoo;	/* original clauses */
+  Cls **lclauses, **lhead, ** EOL;	/* learned clauses */
+  int * soclauses, * sohead, * eoso; /* saved original clauses */
+  int saveorig;
+  int partial;
+#ifdef TRACE
+  int trace;
+  Zhn **zhains, **zhead, **eoz;
+  int ocore;
+#endif
+  FILE * rup;
+  int rupstarted;
+  int rupvariables;
+  int rupclauses;
+  Cls *mtcls;
+  Cls *conflict;
+  Lit **added, **ahead, **eoa;
+  Var **marked, **mhead, **eom;
+  Var **dfs, **dhead, **eod;
+  Cls **resolved, **rhead, **eor;
+  unsigned char *levels, *levelshead, *eolevels;
+  unsigned *dused, *dusedhead, *eodused;
+  unsigned char *buffer, *bhead, *eob;
+  Act vinc, lscore, ilvinc, ifvinc;
+#ifdef VISCORES
+  Act fvinc, nvinc;
+#endif
+  Act cinc, lcinc, ilcinc, fcinc;
+  unsigned srng;
+  size_t current_bytes;
+  size_t max_bytes;
+  size_t recycled;
+  double seconds, flseconds;
+  double entered;
+  unsigned nentered;
+  int measurealltimeinlib;
+  char *rline[2];
+  int szrline, RCOUNT;
+  double levelsum;
+  unsigned iterations;
+  int reports;
+  int lastrheader;
+  unsigned calls;
+  unsigned decisions;
+  unsigned restarts;
+  unsigned simps;
+  unsigned fsimplify;
+  unsigned isimplify;
+  unsigned reductions;
+  unsigned lreduce;
+  unsigned lreduceadjustcnt;
+  unsigned lreduceadjustinc;
+  unsigned lastreduceconflicts;
+  unsigned llocked;	/* locked large learned clauses */
+  unsigned lrestart;
+#ifdef NLUBY
+  unsigned drestart;
+  unsigned ddrestart;
+#else
+  unsigned lubycnt;
+  unsigned lubymaxdelta;
+  int waslubymaxdelta;
+#endif
+  unsigned long long lsimplify;
+  unsigned long long propagations;
+  unsigned long long lpropagations;
+  unsigned fixed;		/* top level assignments */
+#ifndef NFL
+  unsigned failedlits;
+  unsigned ifailedlits;
+  unsigned efailedlits;
+  unsigned flcalls;
+#ifdef STATS
+  unsigned flrounds;
+  unsigned long long flprops;
+  unsigned long long floopsed, fltried, flskipped;
+#endif
+  unsigned long long fllimit;
+  int simplifying;
+  Lit ** saved;
+  unsigned saved_size;
+#endif
+  unsigned conflicts;
+  unsigned contexts;
+  unsigned internals;
+  unsigned noclauses;	/* current number large original clauses */
+  unsigned nlclauses;	/* current number large learned clauses */
+  unsigned olits;		/* current literals in large original clauses */
+  unsigned llits;		/* current literals in large learned clauses */
+  unsigned oadded;		/* added original clauses */
+  unsigned ladded;		/* added learned clauses */
+  unsigned loadded;	/* added original large clauses */
+  unsigned lladded;	/* added learned large clauses */
+  unsigned addedclauses;	/* oadded + ladded */
+  unsigned vused;		/* used variables */
+  unsigned llitsadded;	/* added learned literals */
+  unsigned long long visits;
+#ifdef STATS
+  unsigned loused;		/* used large original clauses */
+  unsigned llused;		/* used large learned clauses */
+  unsigned long long bvisits;
+  unsigned long long tvisits;
+  unsigned long long lvisits;
+  unsigned long long othertrue;
+  unsigned long long othertrue2;
+  unsigned long long othertruel;
+  unsigned long long othertrue2u;
+  unsigned long long othertruelu;
+  unsigned long long ltraversals;
+  unsigned long long traversals;
+#ifdef TRACE
+  unsigned long long antecedents;
+#endif
+  unsigned uips;
+  unsigned znts;
+  unsigned assumptions;
+  unsigned rdecisions;
+  unsigned sdecisions;
+  size_t srecycled;
+  size_t rrecycled;
+  unsigned long long derefs;
+#endif
+  unsigned minimizedllits;
+  unsigned nonminimizedllits;
+#ifndef NADC
+  Lit *** ados, *** hados, *** eados;
+  Lit *** adotab;
+  unsigned nadotab;
+  unsigned szadotab;
+  Cls * adoconflict;
+  unsigned adoconflicts;
+  unsigned adoconflictlimit;
+  int addingtoado;
+  int adodisabled;
+#endif
+  unsigned long long flips;
+#ifdef STATS
+  unsigned long long FORCED;
+  unsigned long long assignments;
+  unsigned inclreduces;
+  unsigned staticphasedecisions;
+  unsigned skippedrestarts;
+#endif
+  int * indices, * ihead, *eoi; 
+  unsigned sdflips;
+
+  unsigned long long saved_flips;
+  unsigned saved_max_var;
+  unsigned min_flipped;
+
+  void * emgr;
+  picosat_malloc enew;
+  picosat_realloc eresize;
+  picosat_free edelete;
+
+  struct {
+    void * state;
+    int (*function) (void *);
+  } interrupt;
+
+#ifdef VISCORES
+  FILE * fviscores;
+#endif
+};
+
+typedef PicoSAT PS;
+
+static Flt
+packflt (unsigned m, int e)
+{
+  Flt res;
+  assert (m < FLTMSB);
+  assert (FLTMINEXPONENT <= e);
+  assert (e <= FLTMAXEXPONENT);
+  res = m | ((unsigned)(e + 128) << 24);
+  return res;
+}
+
+static Flt
+base2flt (unsigned m, int e)
+{
+  if (!m)
+    return ZEROFLT;
+
+  if (m < FLTMSB)
+    {
+      do
+	{
+	  if (e <= FLTMINEXPONENT)
+	    return EPSFLT;
+
+	  e--;
+	  m <<= 1;
+
+	}
+      while (m < FLTMSB);
+    }
+  else
+    {
+      while (m >= FLTCARRY)
+	{
+	  if (e >= FLTMAXEXPONENT)
+	    return INFFLT;
+
+	  e++;
+	  m >>= 1;
+	}
+    }
+
+  m &= ~FLTMSB;
+  return packflt (m, e);
+}
+
+static Flt
+addflt (Flt a, Flt b)
+{
+  unsigned ma, mb, delta;
+  int ea, eb;
+
+  CMPSWAPFLT (a, b);
+  if (!b)
+    return a;
+
+  UNPACKFLT (a, ma, ea);
+  UNPACKFLT (b, mb, eb);
+
+  assert (ea >= eb);
+  delta = ea - eb;
+  if (delta < 32) mb >>= delta; else mb = 0;
+  if (!mb)
+    return a;
+
+  ma += mb;
+  if (ma & FLTCARRY)
+    {
+      if (ea == FLTMAXEXPONENT)
+	return INFFLT;
+
+      ea++;
+      ma >>= 1;
+    }
+
+  assert (ma < FLTCARRY);
+  ma &= FLTMAXMANTISSA;
+
+  return packflt (ma, ea);
+}
+
+static Flt
+mulflt (Flt a, Flt b)
+{
+  unsigned ma, mb;
+  unsigned long long accu;
+  int ea, eb;
+
+  CMPSWAPFLT (a, b);
+  if (!b)
+    return ZEROFLT;
+
+  UNPACKFLT (a, ma, ea);
+  UNPACKFLT (b, mb, eb);
+
+  ea += eb;
+  ea += 24;
+  if (ea > FLTMAXEXPONENT)
+    return INFFLT;
+
+  if (ea < FLTMINEXPONENT)
+    return EPSFLT;
+
+  accu = ma;
+  accu *= mb;
+  accu >>= 24;
+
+  if (accu >= FLTCARRY)
+    {
+      if (ea == FLTMAXEXPONENT)
+	return INFFLT;
+
+      ea++;
+      accu >>= 1;
+
+      if (accu >= FLTCARRY)
+	return INFFLT;
+    }
+
+  assert (accu < FLTCARRY);
+  assert (accu & FLTMSB);
+
+  ma = accu;
+  ma &= ~FLTMSB;
+
+  return packflt (ma, ea);
+}
+
+static Flt
+ascii2flt (const char *str)
+{
+  Flt ten = base2flt (10, 0);
+  Flt onetenth = base2flt (26843546, -28);
+  Flt res = ZEROFLT, tmp, base;
+  const char *p = str;
+  int ch;
+
+  ch = *p++;
+
+  if (ch != '.')
+    {
+      if (!isdigit (ch))
+	return INFFLT;	/* better abort ? */
+
+      res = base2flt (ch - '0', 0);
+
+      while ((ch = *p++))
+	{
+	  if (ch == '.')
+	    break;
+
+	  if (!isdigit (ch))
+	    return INFFLT;	/* better abort? */
+
+	  res = mulflt (res, ten);
+	  tmp = base2flt (ch - '0', 0);
+	  res = addflt (res, tmp);
+	}
+    }
+
+  if (ch == '.')
+    {
+      ch = *p++;
+      if (!isdigit (ch))
+	return INFFLT;	/* better abort ? */
+
+      base = onetenth;
+      tmp = mulflt (base2flt (ch - '0', 0), base);
+      res = addflt (res, tmp);
+
+      while ((ch = *p++))
+	{
+	  if (!isdigit (ch))
+	    return INFFLT;	/* better abort? */
+
+	  base = mulflt (base, onetenth);
+	  tmp = mulflt (base2flt (ch - '0', 0), base);
+	  res = addflt (res, tmp);
+	}
+    }
+
+  return res;
+}
+
+#if defined(VISCORES)
+
+static double
+flt2double (Flt f)
+{
+  double res;
+  unsigned m;
+  int e, i;
+
+  UNPACKFLT (f, m, e);
+  res = m;
+
+  if (e < 0)
+    {
+      for (i = e; i < 0; i++)
+	res *= 0.5;
+    }
+  else
+    {
+      for (i = 0; i < e; i++)
+	res *= 2.0;
+    }
+
+  return res;
+}
+
+#endif
+
+static int
+log2flt (Flt a)
+{
+  return FLTEXPONENT (a) + 24;
+}
+
+static int
+cmpflt (Flt a, Flt b)
+{
+  if (a < b)
+    return -1;
+
+  if (a > b)
+    return 1;
+
+  return 0;
+}
+
+static void *
+new (PS * ps, size_t size)
+{
+  size_t bytes;
+  Blk *b;
+  
+  if (!size)
+    return 0;
+
+  bytes = size + SIZE_OF_BLK;
+
+  if (ps->enew)
+    b = ps->enew (ps->emgr, bytes);
+  else
+    b = malloc (bytes);
+
+  ABORTIF (!b, "out of memory in 'new'");
+#ifndef NDEBUG
+  b->header.size = size;
+#endif
+  ps->current_bytes += size;
+  if (ps->current_bytes > ps->max_bytes)
+    ps->max_bytes = ps->current_bytes;
+  return b->data;
+}
+
+static void
+delete (PS * ps, void *void_ptr, size_t size)
+{
+  size_t bytes;
+  Blk *b;
+
+  if (!void_ptr)
+    {
+      assert (!size);
+      return;
+    }
+
+  assert (size);
+  b = PTR2BLK (void_ptr);
+
+  assert (size <= ps->current_bytes);
+  ps->current_bytes -= size;
+
+  assert (b->header.size == size);
+
+  bytes = size + SIZE_OF_BLK;
+  if (ps->edelete)
+    ps->edelete (ps->emgr, b, bytes);
+  else
+    free (b);
+}
+
+static void *
+resize (PS * ps, void *void_ptr, size_t old_size, size_t new_size)
+{
+  size_t old_bytes, new_bytes;
+  Blk *b;
+
+  b = PTR2BLK (void_ptr);
+
+  assert (old_size <= ps->current_bytes);
+  ps->current_bytes -= old_size;
+
+  if ((old_bytes = old_size))
+    {
+      assert (old_size && b && b->header.size == old_size);
+      old_bytes += SIZE_OF_BLK;
+    }
+  else
+    assert (!b);
+
+  if ((new_bytes = new_size))
+    new_bytes += SIZE_OF_BLK;
+
+  if (ps->eresize)
+    b = ps->eresize (ps->emgr, b, old_bytes, new_bytes);
+  else
+    b = realloc (b, new_bytes);
+
+  if (!new_size)
+    {
+      assert (!b);
+      return 0;
+    }
+
+  ABORTIF (!b, "out of memory in 'resize'");
+#ifndef NDEBUG
+  b->header.size = new_size;
+#endif
+
+  ps->current_bytes += new_size;
+  if (ps->current_bytes > ps->max_bytes)
+    ps->max_bytes = ps->current_bytes;
+
+  return b->data;
+}
+
+static unsigned
+int2unsigned (int l)
+{
+  return (l < 0) ? 1 + 2 * -l : 2 * l;
+}
+
+static Lit *
+int2lit (PS * ps, int l)
+{
+  return ps->lits + int2unsigned (l);
+}
+
+static Lit **
+end_of_lits (Cls * c)
+{
+  return (Lit**)c->lits + c->size;
+}
+
+#if !defined(NDEBUG) || defined(LOGGING)
+
+static void
+dumplits (PS * ps, Lit ** l, Lit ** end)
+{
+  int first;
+  Lit ** p;
+
+  if (l == end)
+    {
+      /* empty clause */
+    }
+  else if (l + 1 == end)
+    {
+      fprintf (ps->out, "%d ", LIT2INT (l[0]));
+    }
+  else
+    { 
+      assert (l + 2 <= end);
+      first = (abs (LIT2INT (l[0])) > abs (LIT2INT (l[1])));
+      fprintf (ps->out, "%d ", LIT2INT (l[first]));
+      fprintf (ps->out, "%d ", LIT2INT (l[!first]));
+      for (p = l + 2; p < end; p++)
+	 fprintf (ps->out, "%d ", LIT2INT (*p));
+    }
+
+  fputc ('0', ps->out);
+}
+
+static void
+dumpcls (PS * ps, Cls * c)
+{
+  Lit **end;
+
+  if (c)
+    {
+      end = end_of_lits (c);
+      dumplits (ps, c->lits, end);
+#ifdef TRACE
+      if (ps->trace)
+	 fprintf (ps->out, " clause(%u)", CLS2IDX (c));
+#endif
+    }
+  else
+    fputs ("DECISION", ps->out);
+}
+
+static void
+dumpclsnl (PS * ps, Cls * c)
+{
+  dumpcls (ps, c);
+  fputc ('\n', ps->out);
+}
+
+void
+dumpcnf (PS * ps)
+{
+  Cls **p, *c;
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+
+      if (!c)
+	continue;
+
+#ifdef TRACE
+      if (c->collected)
+	continue;
+#endif
+
+      dumpclsnl (ps, *p);
+    }
+}
+
+#endif
+
+static void
+delete_prefix (PS * ps)
+{
+  if (!ps->prefix)
+    return;
+    
+  delete (ps, ps->prefix, strlen (ps->prefix) + 1);
+  ps->prefix = 0;
+}
+
+static void
+new_prefix (PS * ps, const char * str)
+{
+  delete_prefix (ps);
+  assert (str);
+  ps->prefix = new (ps, strlen (str) + 1);
+  strcpy (ps->prefix, str);
+}
+
+static PS *
+init (void * pmgr, 
+      picosat_malloc pnew, picosat_realloc presize, picosat_free pdelete)
+{
+  PS * ps;
+
+#if 0
+  int count = 3 - !pnew - !presize - !pdelete;
+
+  ABORTIF (count && !pnew, "API usage: missing 'picosat_set_new'");
+  ABORTIF (count && !presize, "API usage: missing 'picosat_set_resize'");
+  ABORTIF (count && !pdelete, "API usage: missing 'picosat_set_delete'");
+#endif
+
+  ps = pnew ? pnew (pmgr, sizeof *ps) : malloc (sizeof *ps);
+  ABORTIF (!ps, "failed to allocate memory for PicoSAT manager");
+  memset (ps, 0, sizeof *ps);
+
+  ps->emgr = pmgr;
+  ps->enew = pnew;
+  ps->eresize = presize;
+  ps->edelete = pdelete;
+
+  ps->size_vars = 1;
+  ps->state = RESET;
+  ps->defaultphase = JWLPHASE;
+#ifdef TRACE
+  ps->ocore = -1;
+#endif
+  ps->lastrheader = -2;
+#ifndef NADC
+  ps->adoconflictlimit = UINT_MAX;
+#endif
+  ps->min_flipped = UINT_MAX;
+
+  NEWN (ps->lits, 2 * ps->size_vars);
+  NEWN (ps->jwh, 2 * ps->size_vars);
+  NEWN (ps->htps, 2 * ps->size_vars);
+#ifndef NDSC
+  NEWN (ps->dhtps, 2 * ps->size_vars);
+#endif
+  NEWN (ps->impls, 2 * ps->size_vars);
+  NEWN (ps->vars, ps->size_vars);
+  NEWN (ps->rnks, ps->size_vars);
+
+  /* because '0' pos denotes not on heap
+   */
+  ENLARGE (ps->heap, ps->hhead, ps->eoh); 
+  ps->hhead = ps->heap + 1;
+
+  ps->vinc = base2flt (1, 0);		/* initial var activity */
+  ps->ifvinc = ascii2flt ("1.05");	/* var score rescore factor */
+#ifdef VISCORES
+  ps->fvinc = ascii2flt ("0.9523809");	/*     1/f =     1/1.05 */
+  ps->nvinc = ascii2flt ("0.0476191");	/* 1 - 1/f = 1 - 1/1.05 */
+#endif
+  ps->lscore = base2flt (1, 90);	/* var activity rescore limit */
+  ps->ilvinc = base2flt (1, -90);	/* inverse of 'lscore' */
+
+  ps->cinc = base2flt (1, 0);		/* initial clause activity */
+  ps->fcinc = ascii2flt ("1.001");	/* cls activity rescore factor */
+  ps->lcinc = base2flt (1, 90);		/* cls activity rescore limit */
+  ps->ilcinc = base2flt (1, -90);	/* inverse of 'ilcinc' */
+
+  ps->lreduceadjustcnt = ps->lreduceadjustinc = 100;
+  ps->lpropagations = ~0ull;
+
+#ifndef RCODE
+  ps->out = stdout;
+#else
+  ps->out = 0;
+#endif
+  new_prefix (ps, "c ");
+  ps->verbosity = 0;
+  ps->plain = 0;
+
+#ifdef NO_BINARY_CLAUSES
+  memset (&ps->impl, 0, sizeof (ps->impl));
+  ps->impl.size = 2;
+
+  memset (&ps->cimpl, 0, sizeof (ps->impl));
+  ps->cimpl.size = 2;
+#endif
+
+#ifdef VISCORES
+  ps->fviscores = popen (
+    "/usr/bin/gnuplot -background black"
+    " -xrm 'gnuplot*textColor:white'"
+    " -xrm 'gnuplot*borderColor:white'"
+    " -xrm 'gnuplot*axisColor:white'"
+    , "w");
+  fprintf (ps->fviscores, "unset key\n");
+  // fprintf (ps->fviscores, "set log y\n");
+  fflush (ps->fviscores);
+  system ("rm -rf /tmp/picosat-viscores");
+  system ("mkdir /tmp/picosat-viscores");
+  system ("mkdir /tmp/picosat-viscores/data");
+#ifdef WRITEGIF
+  system ("mkdir /tmp/picosat-viscores/gif");
+  fprintf (ps->fviscores,
+           "set terminal gif giant animate opt size 1024,768 x000000 xffffff"
+	   "\n");
+
+  fprintf (ps->fviscores, 
+           "set output \"/tmp/picosat-viscores/gif/animated.gif\"\n");
+#endif
+#endif
+  ps->defaultphase = JWLPHASE;
+  ps->state = READY;
+  ps->last_sat_call_result = 0;
+
+  return ps;
+}
+
+static size_t
+bytes_clause (PS * ps, unsigned size, unsigned learned)
+{
+  size_t res;
+
+  res = sizeof (Cls);
+  res += size * sizeof (Lit *);
+  res -= 2 * sizeof (Lit *);
+
+  if (learned && size > 2)
+    res += sizeof (Act);	/* add activity */
+
+#ifdef TRACE
+  if (ps->trace)
+    res += sizeof (Trd);	/* add trace data */
+#else
+  (void) ps;
+#endif
+
+  return res;
+}
+
+static Cls *
+new_clause (PS * ps, unsigned size, unsigned learned)
+{
+  size_t bytes;
+  void * tmp;
+#ifdef TRACE
+  Trd *trd;
+#endif
+  Cls *res;
+
+  bytes = bytes_clause (ps, size, learned);
+  tmp = new (ps, bytes);
+
+#ifdef TRACE
+  if (ps->trace)
+    {
+      trd = tmp;
+
+      if (learned)
+	trd->idx = LIDX2IDX (ps->lhead - ps->lclauses);
+      else
+	trd->idx = OIDX2IDX (ps->ohead - ps->oclauses);
+
+      res = trd->cls;
+    }
+  else
+#endif
+    res = tmp;
+
+  res->size = size;
+  res->learned = learned;
+
+  res->collect = 0;
+#ifndef NDEBUG
+  res->connected = 0;
+#endif
+  res->locked = 0;
+  res->used = 0;
+#ifdef TRACE
+  res->core = 0;
+  res->collected = 0;
+#endif
+
+  if (learned && size > 2)
+    {
+      Act * p = CLS2ACT (res);
+      *p = ps->cinc;
+    }
+
+  return res;
+}
+
+static void
+delete_clause (PS * ps, Cls * c)
+{
+  size_t bytes;
+#ifdef TRACE
+  Trd *trd;
+#endif
+
+  bytes = bytes_clause (ps, c->size, c->learned);
+
+#ifdef TRACE
+  if (ps->trace)
+    {
+      trd = CLS2TRD (c);
+      delete (ps, trd, bytes);
+    }
+  else
+#endif
+    delete (ps, c, bytes);
+}
+
+static void
+delete_clauses (PS * ps)
+{
+  Cls **p;
+  for (p = SOC; p != EOC; p = NXC (p))
+    if (*p)
+      delete_clause (ps, *p);
+
+  DELETEN (ps->oclauses, ps->eoo - ps->oclauses);
+  DELETEN (ps->lclauses, ps->EOL - ps->lclauses);
+
+  ps->ohead = ps->eoo = ps->lhead = ps->EOL = 0;
+}
+
+#ifdef TRACE
+
+static void
+delete_zhain (PS * ps, Zhn * zhain)
+{
+  const Znt *p, *znt;
+
+  assert (zhain);
+
+  znt = zhain->znt;
+  for (p = znt; *p; p++)
+    ;
+
+  delete (ps, zhain, sizeof (Zhn) + (p - znt) + 1);
+}
+
+static void
+delete_zhains (PS * ps)
+{
+  Zhn **p, *z;
+  for (p = ps->zhains; p < ps->zhead; p++)
+    if ((z = *p))
+      delete_zhain (ps, z);
+
+  DELETEN (ps->zhains, ps->eoz - ps->zhains);
+  ps->eoz = ps->zhead = 0;
+}
+
+#endif
+
+#ifdef NO_BINARY_CLAUSES
+static void
+lrelease (PS * ps, Ltk * stk)
+{
+  if (stk->start)
+    DELETEN (stk->start, (1 << (stk->ldsize)));
+  memset (stk, 0, sizeof (*stk));
+}
+#endif
+
+#ifndef NADC
+
+static unsigned
+llength (Lit ** a)
+{
+  Lit ** p;
+  for (p = a; *p; p++)
+    ;
+  return p - a;
+}
+
+static void
+resetadoconflict (PS * ps)
+{
+  assert (ps->adoconflict);
+  delete_clause (ps, ps->adoconflict);
+  ps->adoconflict = 0;
+}
+
+static void
+reset_ados (PS * ps)
+{
+  Lit *** p;
+
+  for (p = ps->ados; p < ps->hados; p++)
+    DELETEN (*p, llength (*p) + 1);
+
+  DELETEN (ps->ados, ps->eados - ps->ados);
+  ps->hados = ps->eados = 0;
+
+  DELETEN (ps->adotab, ps->szadotab);
+  ps->szadotab = ps->nadotab = 0;
+
+  if (ps->adoconflict)
+    resetadoconflict (ps);
+
+  ps->adoconflicts = 0;
+  ps->adoconflictlimit = UINT_MAX;
+  ps->adodisabled = 0;
+}
+
+#endif
+
+static void
+reset (PS * ps)
+{
+  ABORTIF (!ps || 
+           ps->state == RESET, "API usage: reset without initialization");
+
+  delete_clauses (ps);
+#ifdef TRACE
+  delete_zhains (ps);
+#endif
+#ifdef NO_BINARY_CLAUSES
+  {
+    unsigned i;
+    for (i = 2; i <= 2 * ps->max_var + 1; i++)
+      lrelease (ps, ps->impls + i);
+  }
+#endif
+#ifndef NADC
+  reset_ados (ps);
+#endif
+#ifndef NFL
+  DELETEN (ps->saved, ps->saved_size);
+#endif
+  DELETEN (ps->htps, 2 * ps->size_vars);
+#ifndef NDSC
+  DELETEN (ps->dhtps, 2 * ps->size_vars);
+#endif
+  DELETEN (ps->impls, 2 * ps->size_vars);
+  DELETEN (ps->lits, 2 * ps->size_vars);
+  DELETEN (ps->jwh, 2 * ps->size_vars);
+  DELETEN (ps->vars, ps->size_vars);
+  DELETEN (ps->rnks, ps->size_vars);
+  DELETEN (ps->trail, ps->eot - ps->trail);
+  DELETEN (ps->heap, ps->eoh - ps->heap);
+  DELETEN (ps->als, ps->eoals - ps->als);
+  DELETEN (ps->CLS, ps->eocls - ps->CLS);
+  DELETEN (ps->rils, ps->eorils - ps->rils);
+  DELETEN (ps->cils, ps->eocils - ps->cils);
+  DELETEN (ps->fals, ps->eofals - ps->fals);
+  DELETEN (ps->mass, ps->szmass);
+  DELETEN (ps->mssass, ps->szmssass);
+  DELETEN (ps->mcsass, ps->szmcsass);
+  DELETEN (ps->humus, ps->szhumus);
+  DELETEN (ps->added, ps->eoa - ps->added);
+  DELETEN (ps->marked, ps->eom - ps->marked);
+  DELETEN (ps->dfs, ps->eod - ps->dfs);
+  DELETEN (ps->resolved, ps->eor - ps->resolved);
+  DELETEN (ps->levels, ps->eolevels - ps->levels);
+  DELETEN (ps->dused, ps->eodused - ps->dused);
+  DELETEN (ps->buffer, ps->eob - ps->buffer);
+  DELETEN (ps->indices, ps->eoi - ps->indices);
+  DELETEN (ps->soclauses, ps->eoso - ps->soclauses);
+  delete_prefix (ps);
+  delete (ps, ps->rline[0], ps->szrline);
+  delete (ps, ps->rline[1], ps->szrline);
+  assert (getenv ("LEAK") || !ps->current_bytes);	/* found leak if failing */
+#ifdef VISCORES
+  pclose (ps->fviscores);
+#endif
+  if (ps->edelete)
+    ps->edelete (ps->emgr, ps, sizeof *ps);
+  else
+    free (ps);
+}
+
+inline static void
+tpush (PS * ps, Lit * lit)
+{
+  assert (ps->lits < lit && lit <= ps->lits + 2* ps->max_var + 1);
+  if (ps->thead == ps->eot)
+    {
+      unsigned ttail2count = ps->ttail2 - ps->trail;
+      unsigned ttailcount = ps->ttail - ps->trail;
+#ifndef NADC
+      unsigned ttailadocount = ps->ttailado - ps->trail;
+#endif
+      ENLARGE (ps->trail, ps->thead, ps->eot);
+      ps->ttail = ps->trail + ttailcount;
+      ps->ttail2 = ps->trail + ttail2count;
+#ifndef NADC
+      ps->ttailado = ps->trail + ttailadocount;
+#endif
+    }
+
+  *ps->thead++ = lit;
+}
+
+static void
+assign_reason (PS * ps, Var * v, Cls * reason)
+{
+#if defined(NO_BINARY_CLAUSES) && !defined(NDEBUG)
+  assert (reason != &ps->impl);
+#else
+  (void) ps;
+#endif
+  v->reason = reason;
+}
+
+static void
+assign_phase (PS * ps, Lit * lit)
+{
+  unsigned new_phase, idx;
+  Var * v = LIT2VAR (lit);
+
+#ifndef NFL
+  /* In 'simplifying' mode we only need to keep 'min_flipped' up to date if
+   * we force assignments on the top level.   The other assignments will be
+   * undone and thus we can keep the old saved value of the phase.
+   */
+  if (!ps->LEVEL || !ps->simplifying)
+#endif
+    {
+      new_phase = (LIT2SGN (lit) > 0);
+
+      if (v->assigned)
+	{
+	  ps->sdflips -= ps->sdflips/FFLIPPED;
+
+	  if (new_phase != v->phase)
+	    {
+	      assert (FFLIPPEDPREC >= FFLIPPED);
+	      ps->sdflips += FFLIPPEDPREC / FFLIPPED;
+	      ps->flips++;
+
+	      idx = LIT2IDX (lit);
+	      if (idx < ps->min_flipped)
+		ps->min_flipped = idx;
+
+              NOLOG (fprintf (ps->out, 
+	                      "%sflipped %d\n",
+			       ps->prefix, LIT2INT (lit)));
+	    }
+	}
+
+      v->phase = new_phase;
+      v->assigned = 1;
+    }
+
+  lit->val = TRUE;
+  NOTLIT (lit)->val = FALSE;
+}
+
+inline static void
+assign (PS * ps, Lit * lit, Cls * reason)
+{
+  Var * v = LIT2VAR (lit);
+  assert (lit->val == UNDEF);
+#ifdef STATS
+  ps->assignments++;
+#endif
+  v->level = ps->LEVEL;
+  assign_phase (ps, lit);
+  assign_reason (ps, v, reason);
+  tpush (ps, lit);
+}
+
+inline static int
+cmp_added (PS * ps, Lit * k, Lit * l)
+{
+  Val a = k->val, b = l->val;
+  Var *u, *v;
+  int res;
+
+  if (a == UNDEF && b != UNDEF)
+    return -1;
+
+  if (a != UNDEF && b == UNDEF)
+    return 1;
+
+  u = LIT2VAR (k);
+  v = LIT2VAR (l);
+
+  if (a != UNDEF)
+    {
+      assert (b != UNDEF);
+      res = v->level - u->level;
+      if (res)
+	return res;		/* larger level first */
+    }
+
+  res = cmpflt (VAR2RNK (u)->score, VAR2RNK (v)->score);
+  if (res)
+    return res;			/* smaller activity first */
+
+  return u - v;			/* smaller index first */
+}
+
+static void
+sorttwolits (Lit ** v)
+{
+  Lit * a = v[0], * b = v[1];
+
+  assert (a != b);
+
+  if (a < b)
+    return;
+
+  v[0] = b;
+  v[1] = a;
+}
+
+inline static void
+sortlits (PS * ps, Lit ** v, unsigned size)
+{
+  if (size == 2)
+    sorttwolits (v);	/* same order with and with out 'NO_BINARY_CLAUSES' */
+  else
+    SORT (Lit *, cmp_added, v, size);
+}
+
+#ifdef NO_BINARY_CLAUSES
+static Cls *
+setimpl (PS * ps, Lit * a, Lit * b)
+{
+  assert (!ps->implvalid);
+  assert (ps->impl.size == 2);
+
+  ps->impl.lits[0] = a;
+  ps->impl.lits[1] = b;
+
+  sorttwolits (ps->impl.lits);
+  ps->implvalid = 1;
+
+  return &ps->impl;
+}
+
+static void
+resetimpl (PS * ps)
+{
+  ps->implvalid = 0;
+}
+
+static Cls *
+setcimpl (PS * ps, Lit * a, Lit * b)
+{
+  assert (!ps->cimplvalid);
+  assert (ps->cimpl.size == 2);
+
+  ps->cimpl.lits[0] = a;
+  ps->cimpl.lits[1] = b;
+
+  sorttwolits (ps->cimpl.lits);
+  ps->cimplvalid = 1;
+
+  return &ps->cimpl;
+}
+
+static void
+resetcimpl (PS * ps)
+{
+  assert (ps->cimplvalid);
+  ps->cimplvalid = 0;
+}
+
+#endif
+
+static int
+cmp_ptr (PS * ps, void *l, void *k)
+{
+  (void) ps;
+  return ((char*)l) - (char*)k;		/* arbitrarily already reverse */
+}
+
+static int
+cmp_rnk (Rnk * r, Rnk * s)
+{
+  if (!r->moreimportant && s->moreimportant)
+    return -1;
+
+  if (r->moreimportant && !s->moreimportant)
+    return 1;
+
+  if (!r->lessimportant && s->lessimportant)
+    return 1;
+
+  if (r->lessimportant && !s->lessimportant)
+    return -1;
+
+  if (r->score < s->score)
+    return -1;
+
+  if (r->score > s->score)
+    return 1;
+
+  return -cmp_ptr (0, r, s);
+}
+
+static void
+hup (PS * ps, Rnk * v)
+{
+  int upos, vpos;
+  Rnk *u;
+
+#ifndef NFL
+  assert (!ps->simplifying);
+#endif
+
+  vpos = v->pos;
+
+  assert (0 < vpos);
+  assert (vpos < ps->hhead - ps->heap);
+  assert (ps->heap[vpos] == v);
+
+  while (vpos > 1)
+    {
+      upos = vpos / 2;
+
+      u = ps->heap[upos];
+
+      if (cmp_rnk (u, v) > 0)
+	break;
+
+      ps->heap[vpos] = u;
+      u->pos = vpos;
+
+      vpos = upos;
+    }
+
+  ps->heap[vpos] = v;
+  v->pos = vpos;
+}
+
+static Cls *add_simplified_clause (PS *, int);
+
+inline static void
+add_antecedent (PS * ps, Cls * c)
+{
+  assert (c);
+
+#ifdef NO_BINARY_CLAUSES
+  if (ISLITREASON (c))
+    return;
+
+  if (c == &ps->impl)
+    return;
+#elif defined(STATS) && defined(TRACE)
+  ps->antecedents++;
+#endif
+  if (ps->rhead == ps->eor)
+    ENLARGE (ps->resolved, ps->rhead, ps->eor);
+
+  assert (ps->rhead < ps->eor);
+  *ps->rhead++ = c;
+}
+
+#ifdef TRACE
+
+#ifdef NO_BINARY_CLAUSES
+#error "can not combine TRACE and NO_BINARY_CLAUSES"
+#endif
+
+#endif /* TRACE */
+
+static void
+add_lit (PS * ps, Lit * lit)
+{
+  assert (lit);
+
+  if (ps->ahead == ps->eoa)
+    ENLARGE (ps->added, ps->ahead, ps->eoa);
+
+  *ps->ahead++ = lit;
+}
+
+static void
+push_var_as_marked (PS * ps, Var * v)
+{
+  if (ps->mhead == ps->eom)
+    ENLARGE (ps->marked, ps->mhead, ps->eom);
+
+  *ps->mhead++ = v;
+}
+
+static void
+mark_var (PS * ps, Var * v)
+{
+  assert (!v->mark);
+  v->mark = 1;
+  push_var_as_marked (ps, v);
+}
+
+#ifdef NO_BINARY_CLAUSES
+
+static Cls *
+impl2reason (PS * ps, Lit * lit)
+{
+  Lit * other;
+  Cls * res;
+  other = ps->impl.lits[0];
+  if (lit == other)
+    other = ps->impl.lits[1];
+  assert (other->val == FALSE);
+  res = LIT2REASON (NOTLIT (other));
+  resetimpl (ps);
+  return res;
+}
+
+#endif
+
+/* Whenever we have a top level derived unit we really should derive a unit
+ * clause otherwise the resolutions in 'add_simplified_clause' become
+ * incorrect.
+ */
+static Cls *
+resolve_top_level_unit (PS * ps, Lit * lit, Cls * reason)
+{
+  unsigned count_resolved;
+  Lit **p, **eol, *other;
+  Var *u, *v;
+
+  assert (ps->rhead == ps->resolved);
+  assert (ps->ahead == ps->added);
+
+  add_lit (ps, lit);
+  add_antecedent (ps, reason);
+  count_resolved = 1;
+  v = LIT2VAR (lit);
+
+  eol = end_of_lits (reason);
+  for (p = reason->lits; p < eol; p++)
+    {
+      other = *p;
+      u = LIT2VAR (other);
+      if (u == v)
+	continue;
+
+      add_antecedent (ps, u->reason);
+      count_resolved++;
+    }
+
+  /* Some of the literals could be assumptions.  If at least one
+   * variable is not an assumption, we should resolve.
+   */
+  if (count_resolved >= 2)
+    {
+#ifdef NO_BINARY_CLAUSES
+      if (reason == &ps->impl)
+	resetimpl (ps);
+#endif
+      reason = add_simplified_clause (ps, 1);
+#ifdef NO_BINARY_CLAUSES
+      if (reason->size == 2)
+	{
+	  assert (reason == &ps->impl);
+	  reason = impl2reason (ps, lit);
+	}
+#endif
+      assign_reason (ps, v, reason);
+    }
+  else
+    {
+      ps->ahead = ps->added;
+      ps->rhead = ps->resolved;
+    }
+
+  return reason;
+}
+
+static void
+fixvar (PS * ps, Var * v)
+{
+  Rnk * r;
+
+  assert (VAR2LIT (v) != UNDEF);
+  assert (!v->level);
+
+  ps->fixed++;
+
+  r = VAR2RNK (v);
+  r->score = INFFLT;
+
+#ifndef NFL
+  if (ps->simplifying)
+    return;
+#endif
+
+  if (!r->pos)
+    return;
+
+  hup (ps, r);
+}
+
+static void
+use_var (PS * ps, Var * v)
+{
+  if (v->used)
+    return;
+
+  v->used = 1;
+  ps->vused++;
+}
+
+static void
+assign_forced (PS * ps, Lit * lit, Cls * reason)
+{
+  Var *v;
+
+  assert (reason);
+  assert (lit->val == UNDEF);
+
+#ifdef STATS
+  ps->FORCED++;
+#endif
+  assign (ps, lit, reason);
+
+#ifdef NO_BINARY_CLAUSES
+  assert (reason != &ps->impl);
+  if (ISLITREASON (reason)) 
+    {
+      reason = setimpl (ps, lit, NOTLIT (REASON2LIT (reason)));
+      assert (reason);
+    }
+#endif
+  LOG ( fprintf (ps->out,
+                "%sassign %d at level %d by ",
+                ps->prefix, LIT2INT (lit), ps->LEVEL);
+       dumpclsnl (ps, reason));
+
+  v = LIT2VAR (lit);
+  if (!ps->LEVEL)
+    use_var (ps, v);
+
+  if (!ps->LEVEL && reason->size > 1)
+    {
+      reason = resolve_top_level_unit (ps, lit, reason);
+      assert (reason);
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  if (ISLITREASON (reason) || reason == &ps->impl)
+    {
+      /* DO NOTHING */
+    }
+  else
+#endif
+    {
+      assert (!reason->locked);
+      reason->locked = 1;
+      if (reason->learned && reason->size > 2)
+	ps->llocked++;
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  if (reason == &ps->impl)
+    resetimpl (ps);
+#endif
+
+  if (!ps->LEVEL)
+    fixvar (ps, v);
+}
+
+#ifdef NO_BINARY_CLAUSES
+
+static void
+lpush (PS * ps, Lit * lit, Cls * c)
+{
+  int pos = (c->lits[0] == lit);
+  Ltk * s = LIT2IMPLS (lit);
+  unsigned oldsize, newsize;
+
+  assert (c->size == 2);
+
+  if (!s->start)
+    {
+      assert (!s->count);
+      assert (!s->ldsize);
+      NEWN (s->start, 1);
+    }
+  else 
+    {
+      oldsize = (1 << (s->ldsize));
+      assert (s->count <= oldsize);
+      if (s->count == oldsize)
+	{
+	  newsize = 2 * oldsize;
+	  RESIZEN (s->start, oldsize, newsize);
+	  s->ldsize++;
+	}
+    }
+
+  s->start[s->count++] = c->lits[pos];
+}
+
+#endif
+
+static void
+connect_head_tail (PS * ps, Lit * lit, Cls * c)
+{
+  Cls ** s;
+  assert (c->size >= 1);
+  if (c->size == 2)
+    {
+#ifdef NO_BINARY_CLAUSES
+      lpush (ps, lit, c);
+      return;
+#else
+      s = LIT2IMPLS (lit);
+#endif
+    }
+  else
+    s = LIT2HTPS (lit);
+
+  if (c->lits[0] != lit)
+    {
+      assert (c->size >= 2);
+      assert (c->lits[1] == lit);
+      c->next[1] = *s;
+    }
+  else
+    c->next[0] = *s;
+
+  *s = c;
+}
+
+#ifdef TRACE
+static void
+zpush (PS * ps, Zhn * zhain)
+{
+  assert (ps->trace);
+
+  if (ps->zhead == ps->eoz)
+    ENLARGE (ps->zhains, ps->zhead, ps->eoz);
+
+  *ps->zhead++ = zhain;
+}
+
+static int
+cmp_resolved (PS * ps, Cls * c, Cls * d)
+{
+#ifndef NDEBUG
+  assert (ps->trace);
+#else
+  (void) ps;
+#endif
+  return CLS2IDX (c) - CLS2IDX (d);
+}
+
+static void
+bpushc (PS * ps, unsigned char ch)
+{
+  if (ps->bhead == ps->eob)
+    ENLARGE (ps->buffer, ps->bhead, ps->eob);
+
+  *ps->bhead++ = ch;
+}
+
+static void
+bpushu (PS * ps, unsigned u)
+{
+  while (u & ~0x7f)
+    {
+      bpushc (ps, u | 0x80);
+      u >>= 7;
+    }
+
+  bpushc (ps, u);
+}
+
+static void
+bpushd (PS * ps, unsigned prev, unsigned this)
+{
+  unsigned delta;
+  assert (prev < this);
+  delta = this - prev;
+  bpushu (ps, delta);
+}
+
+static void
+add_zhain (PS * ps)
+{
+  unsigned prev, this, count, rcount;
+  Cls **p, *c;
+  Zhn *res;
+
+  assert (ps->trace);
+  assert (ps->bhead == ps->buffer);
+  assert (ps->rhead > ps->resolved);
+
+  rcount = ps->rhead - ps->resolved;
+  SORT (Cls *, cmp_resolved, ps->resolved, rcount);
+
+  prev = 0;
+  for (p = ps->resolved; p < ps->rhead; p++)
+    {
+      c = *p;
+      this = CLS2TRD (c)->idx;
+      bpushd (ps, prev, this);
+      prev = this;
+    }
+  bpushc (ps, 0);
+
+  count = ps->bhead - ps->buffer;
+
+  res = new (ps, sizeof (Zhn) + count);
+  res->core = 0;
+  res->ref = 0;
+  memcpy (res->znt, ps->buffer, count);
+
+  ps->bhead = ps->buffer;
+#ifdef STATS
+  ps->znts += count - 1;
+#endif
+  zpush (ps, res);
+}
+
+#endif
+
+static void
+add_resolved (PS * ps, int learned)
+{
+#if defined(STATS) || defined(TRACE)
+  Cls **p, *c;
+
+  for (p = ps->resolved; p < ps->rhead; p++)
+    {
+      c = *p;
+      if (c->used)
+	continue;
+
+      c->used = 1;
+
+      if (c->size <= 2)
+	continue;
+
+#ifdef STATS
+      if (c->learned)
+	ps->llused++;
+      else
+	ps->loused++;
+#endif
+    }
+#endif
+
+#ifdef TRACE
+  if (learned && ps->trace)
+    add_zhain (ps);
+#else
+  (void) learned;
+#endif
+  ps->rhead = ps->resolved;
+}
+
+static void
+incjwh (PS * ps, Cls * c)
+{
+  Lit **p, *lit, ** eol;
+  Flt * f, inc, sum;
+  unsigned size = 0;
+  Var * v;
+  Val val;
+
+  eol = end_of_lits (c);
+
+  for (p = c->lits; p < eol; p++)
+    {
+      lit = *p;
+      val = lit->val;
+
+      if (val && ps->LEVEL > 0)
+	{
+	  v = LIT2VAR (lit);
+	  if (v->level > 0)
+	    val = UNDEF;
+	}
+
+      if (val == TRUE)
+	return;
+
+      if (val != FALSE)
+	size++;
+    }
+
+  inc = base2flt (1, -size);
+
+  for (p = c->lits; p < eol; p++)
+    {
+      lit = *p;
+      f = LIT2JWH (lit);
+      sum = addflt (*f, inc);
+      *f = sum;
+    }
+}
+
+static void
+write_rup_header (PS * ps, FILE * file)
+{
+  char line[80];
+  int i;
+
+  sprintf (line, "%%RUPD32 %u %u", ps->rupvariables, ps->rupclauses);
+
+  fputs (line, file);
+  for (i = 255 - strlen (line); i >= 0; i--)
+    fputc (' ', file);
+
+  fputc ('\n', file);
+  fflush (file);
+}
+
+static Cls *
+add_simplified_clause (PS * ps, int learned)
+{
+  unsigned num_true, num_undef, num_false, size, count_resolved;
+  Lit **p, **q, *lit, ** end;
+  unsigned litlevel, glue;
+  Cls *res, * reason;
+  int reentered;
+  Val val;
+  Var *v;
+#if !defined(NDEBUG) && defined(TRACE)
+  unsigned idx;
+#endif
+
+  reentered = 0;
+
+REENTER:
+
+  size = ps->ahead - ps->added;
+
+  add_resolved (ps, learned);
+
+  if (learned)
+    {
+      ps->ladded++;
+      ps->llitsadded += size;
+      if (size > 2)
+	{
+	  ps->lladded++;
+	  ps->nlclauses++;
+	  ps->llits += size;
+	}
+    }
+  else
+    {
+      ps->oadded++;
+      if (size > 2)
+	{
+	  ps->loadded++;
+	  ps->noclauses++;
+	  ps->olits += size;
+	}
+    }
+
+  ps->addedclauses++;
+  assert (ps->addedclauses == ps->ladded + ps->oadded);
+
+#ifdef NO_BINARY_CLAUSES
+  if (size == 2)
+    res = setimpl (ps, ps->added[0], ps->added[1]);
+  else
+#endif
+    {
+      sortlits (ps, ps->added, size); 
+
+      if (learned)
+	{
+	  if (ps->lhead == ps->EOL)
+	    {
+	      ENLARGE (ps->lclauses, ps->lhead, ps->EOL);
+
+	      /* A very difficult to find bug, which only occurs if the
+	       * learned clauses stack is immediately allocated before the
+	       * original clauses stack without padding.  In this case, we
+	       * have 'SOC == EOC', which terminates all loops using the
+	       * idiom 'for (p = SOC; p != EOC; p = NXC(p))' immediately.
+	       * Unfortunately this occurred in 'fix_clause_lits' after
+	       * using a recent version of the memory allocator of 'Google'
+	       * perftools in the context of one large benchmark for 
+	       * our SMT solver 'Boolector'.
+	       */
+	      if (ps->EOL == ps->oclauses)
+		ENLARGE (ps->lclauses, ps->lhead, ps->EOL);
+	    }
+
+#if !defined(NDEBUG) && defined(TRACE)
+	  idx = LIDX2IDX (ps->lhead - ps->lclauses);
+#endif
+	}
+      else
+	{
+	  if (ps->ohead == ps->eoo)
+	    {
+	      ENLARGE (ps->oclauses, ps->ohead, ps->eoo);
+	      if (ps->EOL == ps->oclauses)
+		ENLARGE (ps->oclauses, ps->ohead, ps->eoo);	/* ditto */
+	    }
+
+#if !defined(NDEBUG) && defined(TRACE)
+	  idx = OIDX2IDX (ps->ohead - ps->oclauses);
+#endif
+	}
+
+      assert (ps->EOL != ps->oclauses);			/* ditto */
+
+      res = new_clause (ps, size, learned);
+
+      glue = 0;
+
+      if (learned)
+	{
+	  assert (ps->dusedhead == ps->dused);
+
+	  for (p = ps->added; p < ps->ahead; p++) 
+	    {
+	      lit = *p;
+	      if (lit->val)
+		{
+		  litlevel = LIT2VAR (lit)->level;
+		  assert (litlevel <= ps->LEVEL);
+		  while (ps->levels + litlevel >= ps->levelshead)
+		    {
+		      if (ps->levelshead >= ps->eolevels)
+			ENLARGE (ps->levels, ps->levelshead, ps->eolevels);
+		      assert (ps->levelshead < ps->eolevels);
+		      *ps->levelshead++ = 0;
+		    }
+		  if (!ps->levels[litlevel])
+		    {
+		      if (ps->dusedhead >= ps->eodused)
+			ENLARGE (ps->dused, ps->dusedhead, ps->eodused);
+		      assert (ps->dusedhead < ps->eodused);
+		      *ps->dusedhead++ = litlevel;
+		      ps->levels[litlevel] = 1;
+		      glue++;
+		    }
+		}
+	      else
+		glue++;
+	    }
+
+	  while (ps->dusedhead > ps->dused) 
+	    {
+	      litlevel = *--ps->dusedhead;
+	      assert (ps->levels + litlevel < ps->levelshead);
+	      assert (ps->levels[litlevel]);
+	      ps->levels[litlevel] = 0;
+	    }
+	}
+
+      assert (glue <= MAXGLUE);
+      res->glue = glue;
+
+#if !defined(NDEBUG) && defined(TRACE)
+      if (ps->trace)
+	assert (CLS2IDX (res) == idx);
+#endif
+      if (learned)
+	*ps->lhead++ = res;
+      else
+	*ps->ohead++ = res;
+
+#if !defined(NDEBUG) && defined(TRACE)
+      if (ps->trace && learned)
+	assert (ps->zhead - ps->zhains == ps->lhead - ps->lclauses);
+#endif
+      assert (ps->lhead != ps->oclauses);		/* ditto */
+    }
+
+  if (learned && ps->rup)
+    {
+      if (!ps->rupstarted)
+	{
+	  write_rup_header (ps, ps->rup);
+	  ps->rupstarted = 1;
+	}
+    }
+
+  num_true = num_undef = num_false = 0;
+
+  q = res->lits;
+  for (p = ps->added; p < ps->ahead; p++)
+    {
+      lit = *p;
+      *q++ = lit;
+
+      if (learned && ps->rup)
+	fprintf (ps->rup, "%d ", LIT2INT (lit));
+
+      val = lit->val;
+
+      num_true += (val == TRUE);
+      num_undef += (val == UNDEF);
+      num_false += (val == FALSE);
+    }
+  assert (num_false + num_true + num_undef == size);
+
+  if (learned && ps->rup)
+    fputs ("0\n", ps->rup);
+
+  ps->ahead = ps->added;		/* reset */
+
+  if (!reentered)				// TODO merge
+  if (size > 0)
+    {
+      assert (size <= 2 || !reentered);		// TODO remove
+      connect_head_tail (ps, res->lits[0], res);
+      if (size > 1)
+	connect_head_tail (ps, res->lits[1], res);
+    }
+
+  if (size == 0)
+    {
+      if (!ps->mtcls)
+	ps->mtcls = res;
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  if (size != 2)
+#endif
+#ifndef NDEBUG
+    res->connected = 1;
+#endif
+
+  LOG ( fprintf (ps->out, "%s%s ", ps->prefix, learned ? "learned" : "original");
+        dumpclsnl (ps, res));
+
+  /* Shrink clause by resolving it against top level assignments.
+   */
+  if (!ps->LEVEL && num_false > 0)
+    {
+      assert (ps->ahead == ps->added);
+      assert (ps->rhead == ps->resolved);
+
+      count_resolved = 1;
+      add_antecedent (ps, res);
+
+      end = end_of_lits (res);
+      for (p = res->lits; p < end; p++)
+	{
+	  lit = *p;
+	  v = LIT2VAR (lit);
+	  use_var (ps, v);
+
+	  if (lit->val == FALSE)
+	    {
+	      add_antecedent (ps, v->reason);
+	      count_resolved++;
+	    }
+	  else
+	    add_lit (ps, lit);
+	}
+
+      assert (count_resolved >= 2);
+
+      learned = 1;
+#ifdef NO_BINARY_CLAUSES
+      if (res == &ps->impl)
+	resetimpl (ps);
+#endif
+      reentered = 1;
+      goto REENTER;		/* and return simplified clause */
+    }
+
+  if (!num_true && num_undef == 1)	/* unit clause */
+    {
+      lit = 0;
+      for (p = res->lits; p < res->lits + size; p++)
+	{
+	  if ((*p)->val == UNDEF)
+	    lit = *p;
+
+	  v = LIT2VAR (*p);
+	  use_var (ps, v);
+	}
+      assert (lit);
+
+      reason = res;
+#ifdef NO_BINARY_CLAUSES
+      if (size == 2)
+        {
+	  Lit * other = res->lits[0];
+	  if (other == lit)
+	    other = res->lits[1];
+
+	  assert (other->val == FALSE);
+	  reason = LIT2REASON (NOTLIT (other));
+	}
+#endif
+      assign_forced (ps, lit, reason);
+      num_true++;
+    }
+
+  if (num_false == size && !ps->conflict)
+    {
+#ifdef NO_BINARY_CLAUSES
+      if (res == &ps->impl)
+	ps->conflict = setcimpl (ps, res->lits[0], res->lits[1]);
+      else
+#endif
+      ps->conflict = res;
+    }
+
+  if (!learned && !num_true && num_undef)
+    incjwh (ps, res);
+
+#ifdef NO_BINARY_CLAUSES
+  if (res == &ps->impl)
+    resetimpl (ps);
+#endif
+  return res;
+}
+
+static int
+trivial_clause (PS * ps)
+{
+  Lit **p, **q, *prev;
+  Var *v;
+
+  SORT (Lit *, cmp_ptr, ps->added,  ps->ahead - ps->added);
+
+  prev = 0;
+  q = ps->added;
+  for (p = q; p < ps->ahead; p++)
+    {
+      Lit *this = *p;
+
+      v = LIT2VAR (this);
+
+      if (prev == this)		/* skip repeated literals */
+	continue;
+
+      /* Top level satisfied ? 
+       */
+      if (this->val == TRUE && !v->level)
+	 return 1;
+
+      if (prev == NOTLIT (this))/* found pair of dual literals */
+	return 1;
+
+      *q++ = prev = this;
+    }
+
+  ps->ahead = q;			/* shrink */
+
+  return 0;
+}
+
+static void
+simplify_and_add_original_clause (PS * ps)
+{
+#ifdef NO_BINARY_CLAUSES
+  Cls * c;
+#endif
+  if (trivial_clause (ps))
+    {
+      ps->ahead = ps->added;
+
+      if (ps->ohead == ps->eoo)
+	ENLARGE (ps->oclauses, ps->ohead, ps->eoo);
+
+      *ps->ohead++ = 0;
+
+      ps->addedclauses++;
+      ps->oadded++;
+    }
+  else
+    {
+      if (ps->CLS != ps->clshead)
+	add_lit (ps, NOTLIT (ps->clshead[-1]));
+
+#ifdef NO_BINARY_CLAUSES
+      c = 
+#endif
+      add_simplified_clause (ps, 0);
+#ifdef NO_BINARY_CLAUSES
+      if (c == &ps->impl) assert (!ps->implvalid);
+#endif
+    }
+}
+
+#ifndef NADC
+
+static void
+add_ado (PS * ps)
+{
+  unsigned len = ps->ahead - ps->added;
+  Lit ** ado, ** p, ** q, *lit;
+  Var * v, * u;
+
+#ifdef TRACE
+  assert (!ps->trace);
+#endif
+
+  ABORTIF (ps->ados < ps->hados && llength (ps->ados[0]) != len,
+           "internal: non matching all different constraint object lengths");
+
+  if (ps->hados == ps->eados)
+    ENLARGE (ps->ados, ps->hados, ps->eados);
+
+  NEWN (ado, len + 1);
+  *ps->hados++ = ado;
+
+  p = ps->added;
+  q = ado;
+  u = 0;
+  while (p < ps->ahead)
+    {
+      lit = *p++;
+      v = LIT2VAR (lit);
+      ABORTIF (v->inado, 
+               "internal: variable in multiple all different objects");
+      v->inado = ado;
+      if (!u && !lit->val)
+	u = v;
+      *q++ = lit;
+    }
+
+  assert (q == ado + len);
+  *q++ = 0;
+
+  /* TODO simply do a conflict test as in propado */
+
+  ABORTIF (!u,
+    "internal: "
+    "adding fully instantiated all different object not implemented yet");
+
+  assert (u);
+  assert (u->inado == ado);
+  assert (!u->ado);
+  u->ado = ado;
+
+  ps->ahead = ps->added;
+}
+
+#endif
+
+static void
+hdown (PS * ps, Rnk * r)
+{
+  unsigned end, rpos, cpos, opos;
+  Rnk *child, *other;
+
+  assert (r->pos > 0);
+  assert (ps->heap[r->pos] == r);
+
+  end = ps->hhead - ps->heap;
+  rpos = r->pos;
+
+  for (;;)
+    {
+      cpos = 2 * rpos;
+      if (cpos >= end)
+	break;
+
+      opos = cpos + 1;
+      child = ps->heap[cpos];
+
+      if (cmp_rnk (r, child) < 0)
+	{
+	  if (opos < end)
+	    {
+	      other = ps->heap[opos];
+
+	      if (cmp_rnk (child, other) < 0)
+		{
+		  child = other;
+		  cpos = opos;
+		}
+	    }
+	}
+      else if (opos < end)
+	{
+	  child = ps->heap[opos];
+
+	  if (cmp_rnk (r, child) >= 0)
+	    break;
+
+	  cpos = opos;
+	}
+      else
+	break;
+
+      ps->heap[rpos] = child;
+      child->pos = rpos;
+      rpos = cpos;
+    }
+
+  r->pos = rpos;
+  ps->heap[rpos] = r;
+}
+
+static Rnk *
+htop (PS * ps)
+{
+  assert (ps->hhead > ps->heap + 1);
+  return ps->heap[1];
+}
+
+static Rnk *
+hpop (PS * ps)
+{
+  Rnk *res, *last;
+  unsigned end;
+
+  assert (ps->hhead > ps->heap + 1);
+
+  res = ps->heap[1];
+  res->pos = 0;
+
+  end = --ps->hhead - ps->heap;
+  if (end == 1)
+    return res;
+
+  last = ps->heap[end];
+
+  ps->heap[last->pos = 1] = last;
+  hdown (ps, last);
+
+  return res;
+}
+
+inline static void
+hpush (PS * ps, Rnk * r)
+{
+  assert (!r->pos);
+
+  if (ps->hhead == ps->eoh)
+    ENLARGE (ps->heap, ps->hhead, ps->eoh);
+
+  r->pos = ps->hhead++ - ps->heap;
+  ps->heap[r->pos] = r;
+  hup (ps, r);
+}
+
+static void
+fix_trail_lits (PS * ps, long delta)
+{
+  Lit **p;
+  for (p = ps->trail; p < ps->thead; p++)
+    *p += delta;
+}
+
+#ifdef NO_BINARY_CLAUSES
+static void
+fix_impl_lits (PS * ps, long delta)
+{
+  Ltk * s;
+  Lit ** p;
+
+  for (s = ps->impls + 2; s <= ps->impls + 2 * ps->max_var + 1; s++)
+    for (p = s->start; p < s->start + s->count; p++)
+      *p += delta;
+}
+#endif
+
+static void
+fix_clause_lits (PS * ps, long delta)
+{
+  Cls **p, *clause;
+  Lit **q, *lit, **eol;
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      clause = *p;
+      if (!clause)
+	continue;
+
+      q = clause->lits;
+      eol = end_of_lits (clause);
+      while (q < eol)
+	{
+	  assert (q - clause->lits <= (int) clause->size);
+	  lit = *q;
+	  lit += delta;
+	  *q++ = lit;
+	}
+    }
+}
+
+static void
+fix_added_lits (PS * ps, long delta)
+{
+  Lit **p;
+  for (p = ps->added; p < ps->ahead; p++)
+    *p += delta;
+}
+
+static void
+fix_assumed_lits (PS * ps, long delta)
+{
+  Lit **p;
+  for (p = ps->als; p < ps->alshead; p++)
+    *p += delta;
+}
+
+static void
+fix_cls_lits (PS * ps, long delta)
+{
+  Lit **p;
+  for (p = ps->CLS; p < ps->clshead; p++)
+    *p += delta;
+}
+
+static void
+fix_heap_rnks (PS * ps, long delta)
+{
+  Rnk **p;
+
+  for (p = ps->heap + 1; p < ps->hhead; p++)
+    *p += delta;
+}
+
+#ifndef NADC
+
+static void
+fix_ado (long delta, Lit ** ado)
+{
+  Lit ** p;
+  for (p = ado; *p; p++)
+    *p += delta;
+}
+
+static void
+fix_ados (PS * ps, long delta)
+{
+  Lit *** p;
+
+  for (p = ps->ados; p < ps->hados; p++)
+    fix_ado (delta, *p);
+}
+
+#endif
+
+static void
+enlarge (PS * ps, unsigned new_size_vars)
+{
+  long rnks_delta, lits_delta;
+  Lit *old_lits = ps->lits;
+  Rnk *old_rnks = ps->rnks;
+
+  RESIZEN (ps->lits, 2 * ps->size_vars, 2 * new_size_vars);
+  RESIZEN (ps->jwh, 2 * ps->size_vars, 2 * new_size_vars);
+  RESIZEN (ps->htps, 2 * ps->size_vars, 2 * new_size_vars);
+#ifndef NDSC
+  RESIZEN (ps->dhtps, 2 * ps->size_vars, 2 * new_size_vars);
+#endif
+  RESIZEN (ps->impls, 2 * ps->size_vars, 2 * new_size_vars);
+  RESIZEN (ps->vars, ps->size_vars, new_size_vars);
+  RESIZEN (ps->rnks, ps->size_vars, new_size_vars);
+
+  if ((lits_delta = ps->lits - old_lits))
+    {
+      fix_trail_lits (ps, lits_delta);
+      fix_clause_lits (ps, lits_delta);
+      fix_added_lits (ps, lits_delta);
+      fix_assumed_lits (ps, lits_delta);
+      fix_cls_lits (ps, lits_delta);
+#ifdef NO_BINARY_CLAUSES
+      fix_impl_lits (ps, lits_delta);
+#endif
+#ifndef NADC
+      fix_ados (ps, lits_delta);
+#endif
+    }
+
+  if ((rnks_delta = ps->rnks - old_rnks))
+    {
+      fix_heap_rnks (ps, rnks_delta);
+    }
+
+  assert (ps->mhead == ps->marked);
+
+  ps->size_vars = new_size_vars;
+}
+
+static void
+unassign (PS * ps, Lit * lit)
+{
+  Cls *reason;
+  Var *v;
+  Rnk *r;
+
+  assert (lit->val == TRUE);
+
+  LOG ( fprintf (ps->out, "%sunassign %d\n", ps->prefix, LIT2INT (lit)));
+
+  v = LIT2VAR (lit);
+  reason = v->reason;
+
+#ifdef NO_BINARY_CLAUSES
+  assert (reason != &ps->impl);
+  if (ISLITREASON (reason))
+    {
+      /* DO NOTHING */
+    }
+  else
+#endif
+  if (reason)
+    {
+      assert (reason->locked);
+      reason->locked = 0;
+      if (reason->learned && reason->size > 2)
+	{
+	  assert (ps->llocked > 0);
+	  ps->llocked--;
+	}
+    }
+
+  lit->val = UNDEF;
+  NOTLIT (lit)->val = UNDEF;
+
+  r = VAR2RNK (v);
+  if (!r->pos)
+    hpush (ps, r);
+
+#ifndef NDSC
+  {
+    Cls * p, * next, ** q;
+
+    q = LIT2DHTPS (lit);
+    p = *q;
+    *q = 0;
+
+    while (p)
+      {
+	Lit * other = p->lits[0];
+
+	if (other == lit)
+	  {
+	    other = p->lits[1];
+	    q = p->next + 1;
+	  }
+	else
+	  {
+	    assert (p->lits[1] == lit);
+	    q = p->next;
+	  }
+
+	next = *q;
+	*q = *LIT2HTPS (other);
+	*LIT2HTPS (other) = p;
+	p = next;
+      }
+  }
+#endif
+
+#ifndef NADC
+  if (v->adotabpos)
+    {
+      assert (ps->nadotab);
+      assert (*v->adotabpos == v->ado);
+
+      *v->adotabpos = 0;
+      v->adotabpos = 0;
+
+      ps->nadotab--;
+    }
+#endif
+}
+
+static Cls *
+var2reason (PS * ps, Var * var)
+{
+  Cls * res = var->reason;
+#ifdef NO_BINARY_CLAUSES
+  Lit * this, * other;
+  if (ISLITREASON (res))
+    {
+      this = VAR2LIT (var);
+      if (this->val == FALSE)
+	this = NOTLIT (this);
+
+      other = REASON2LIT (res);
+      assert (other->val == TRUE);
+      assert (this->val == TRUE);
+      res = setimpl (ps, NOTLIT (other), this);
+    }
+#else
+  (void) ps;
+#endif
+  return res;
+}
+
+static void
+mark_clause_to_be_collected (Cls * c)
+{
+  assert (!c->collect);
+  c->collect = 1;
+}
+
+static void
+undo (PS * ps, unsigned new_level)
+{
+  Lit *lit;
+  Var *v;
+
+  while (ps->thead > ps->trail)
+    {
+      lit = *--ps->thead;
+      v = LIT2VAR (lit);
+      if (v->level == new_level)
+	{
+	  ps->thead++;		/* fix pre decrement */
+	  break;
+	}
+
+      unassign (ps, lit);
+    }
+
+  ps->LEVEL = new_level;
+  ps->ttail = ps->thead;
+  ps->ttail2 = ps->thead;
+#ifndef NADC
+  ps->ttailado = ps->thead;
+#endif
+
+#ifdef NO_BINARY_CLAUSES
+  if (ps->conflict == &ps->cimpl)
+    resetcimpl (ps);
+#endif
+#ifndef NADC
+  if (ps->conflict && ps->conflict == ps->adoconflict)
+    resetadoconflict (ps);
+#endif
+  ps->conflict = ps->mtcls;
+  if (ps->LEVEL < ps->adecidelevel)
+    {
+      assert (ps->als < ps->alshead);
+      ps->adecidelevel = 0;
+      ps->alstail = ps->als;
+    }
+  LOG ( fprintf (ps->out, "%sback to level %u\n", ps->prefix, ps->LEVEL));
+}
+
+#ifndef NDEBUG
+
+static int
+clause_satisfied (Cls * c)
+{
+  Lit **p, **eol, *lit;
+
+  eol = end_of_lits (c);
+  for (p = c->lits; p < eol; p++)
+    {
+      lit = *p;
+      if (lit->val == TRUE)
+	return 1;
+    }
+
+  return 0;
+}
+
+static void
+original_clauses_satisfied (PS * ps)
+{
+  Cls **p, *c;
+
+  for (p = ps->oclauses; p < ps->ohead; p++)
+    {
+      c = *p;
+
+      if (!c)
+	continue;
+
+      if (c->learned)
+	continue;
+
+      assert (clause_satisfied (c));
+    }
+}
+
+static void
+assumptions_satisfied (PS * ps)
+{
+  Lit *lit, ** p;
+
+  for (p = ps->als; p < ps->alshead; p++)
+    {
+      lit = *p;
+      assert (lit->val == TRUE);
+    }
+}
+
+#endif
+
+static void
+sflush (PS * ps)
+{
+  double now = picosat_time_stamp ();
+  double delta = now - ps->entered;
+  delta = (delta < 0) ? 0 : delta;
+  ps->seconds += delta;
+  ps->entered = now;
+}
+
+static double
+mb (PS * ps)
+{
+  return ps->current_bytes / (double) (1 << 20);
+}
+
+static double
+avglevel (PS * ps)
+{
+  return ps->decisions ? ps->levelsum / ps->decisions : 0.0;
+}
+
+static void
+rheader (PS * ps)
+{
+  assert (ps->lastrheader <= ps->reports);
+
+  if (ps->lastrheader == ps->reports)
+    return;
+
+  ps->lastrheader = ps->reports;
+
+   fprintf (ps->out, "%s\n", ps->prefix);
+   fprintf (ps->out, "%s %s\n", ps->prefix, ps->rline[0]);
+   fprintf (ps->out, "%s %s\n", ps->prefix, ps->rline[1]);
+   fprintf (ps->out, "%s\n", ps->prefix);
+}
+
+static unsigned
+dynamic_flips_per_assignment_per_mille (PS * ps)
+{
+  assert (FFLIPPEDPREC >= 1000);
+  return ps->sdflips / (FFLIPPEDPREC / 1000);
+}
+
+#ifdef NLUBY
+
+static int
+high_agility (PS * ps)
+{
+  return dynamic_flips_per_assignment_per_mille (ps) >= 200;
+}
+
+static int
+very_high_agility (PS * ps)
+{
+  return dynamic_flips_per_assignment_per_mille (ps) >= 250;
+}
+
+#else
+
+static int
+medium_agility (PS * ps)
+{
+  return dynamic_flips_per_assignment_per_mille (ps) >= 230;
+}
+
+#endif
+
+static void
+relemdata (PS * ps)
+{
+  char *p;
+  int x;
+
+  if (ps->reports < 0)
+    {
+      /* strip trailing white space 
+       */
+      for (x = 0; x <= 1; x++)
+	{
+	  p = ps->rline[x] + strlen (ps->rline[x]);
+	  while (p-- > ps->rline[x])
+	    {
+	      if (*p != ' ')
+		break;
+
+	      *p = 0;
+	    }
+	}
+
+      rheader (ps);
+    }
+  else
+    fputc ('\n', ps->out);
+
+  ps->RCOUNT = 0;
+}
+
+static void
+relemhead (PS * ps, const char * name, int fp, double val)
+{
+  int x, y, len, size;
+  const char *fmt;
+  unsigned tmp, e;
+
+  if (ps->reports < 0)
+    {
+      x = ps->RCOUNT & 1;
+      y = (ps->RCOUNT / 2) * 12 + x * 6;
+
+      if (ps->RCOUNT == 1)
+	sprintf (ps->rline[1], "%6s", "");
+
+      len = strlen (name);
+      while (ps->szrline <= len + y + 1)
+	{
+	  size = ps->szrline ? 2 * ps->szrline : 128;
+	  ps->rline[0] = resize (ps, ps->rline[0], ps->szrline, size);
+	  ps->rline[1] = resize (ps, ps->rline[1], ps->szrline, size);
+	  ps->szrline = size;
+	}
+
+      fmt = (len <= 6) ? "%6s%10s" : "%-10s%4s";
+      sprintf (ps->rline[x] + y, fmt, name, "");
+    }
+  else if (val < 0)
+    {
+      assert (fp);
+
+      if (val > -100 && (tmp = val * 10.0 - 0.5) > -1000.0)
+	{
+	   fprintf (ps->out, "-%4.1f ", -tmp / 10.0);
+	}
+      else
+	{
+	  tmp = -val / 10.0 + 0.5;
+	  e = 1;
+	  while (tmp >= 100)
+	    {
+	      tmp /= 10;
+	      e++;
+	    }
+
+	   fprintf (ps->out, "-%2ue%u ", tmp, e);
+	}
+    }
+  else
+    {
+      if (fp && val < 1000 && (tmp = val * 10.0 + 0.5) < 10000)
+	{
+	   fprintf (ps->out, "%5.1f ", tmp / 10.0);
+	}
+      else if (!fp && (tmp = val) < 100000)
+	{
+	   fprintf (ps->out, "%5u ", tmp);
+	}
+      else
+	{
+	  tmp = val / 10.0 + 0.5;
+	  e = 1;
+
+	  while (tmp >= 1000)
+	    {
+	      tmp /= 10;
+	      e++;
+	    }
+
+	   fprintf (ps->out, "%3ue%u ", tmp, e);
+	}
+    }
+
+  ps->RCOUNT++;
+}
+
+inline static void
+relem (PS * ps, const char *name, int fp, double val)
+{
+  if (name)
+    relemhead (ps, name, fp, val);
+  else
+    relemdata (ps);
+}
+
+static unsigned
+reduce_limit_on_lclauses (PS * ps)
+{
+  unsigned res = ps->lreduce;
+  res += ps->llocked;
+  return res;
+}
+
+static void
+report (PS * ps, int replevel, char type)
+{
+  int rounds;
+
+#ifdef RCODE
+  (void) type;
+#endif
+
+  if (ps->verbosity < replevel)
+    return;
+
+  sflush (ps);
+
+  if (!ps->reports)
+    ps->reports = -1;
+
+  for (rounds = (ps->reports < 0) ? 2 : 1; rounds; rounds--)
+    {
+      if (ps->reports >= 0)
+	 fprintf (ps->out, "%s%c ", ps->prefix, type);
+
+      relem (ps, "seconds", 1, ps->seconds);
+      relem (ps, "level", 1, avglevel (ps));
+      assert (ps->fixed <=  ps->max_var);
+      relem (ps, "variables", 0, ps->max_var - ps->fixed);
+      relem (ps, "used", 1, PERCENT (ps->vused, ps->max_var));
+      relem (ps, "original", 0, ps->noclauses);
+      relem (ps, "conflicts", 0, ps->conflicts);
+      // relem (ps, "decisions", 0, ps->decisions);
+      // relem (ps, "conf/dec", 1, PERCENT(ps->conflicts,ps->decisions));
+      // relem (ps, "limit", 0, reduce_limit_on_lclauses (ps));
+      relem (ps, "learned", 0, ps->nlclauses);
+      // relem (ps, "limit", 1, PERCENT (ps->nlclauses, reduce_limit_on_lclauses (ps)));
+      relem (ps, "limit", 0, ps->lreduce);
+#ifdef STATS
+      relem (ps, "learning", 1, PERCENT (ps->llused, ps->lladded));
+#endif
+      relem (ps, "agility", 1, dynamic_flips_per_assignment_per_mille (ps) / 10.0);
+      // relem (ps, "original", 0, ps->noclauses);
+      relem (ps, "MB", 1, mb (ps));
+      // relem (ps, "lladded", 0, ps->lladded);
+      // relem (ps, "llused", 0, ps->llused);
+
+      relem (ps, 0, 0, 0);
+
+      ps->reports++;
+    }
+
+  /* Adapt this to the number of rows in your terminal.
+   */
+  #define ROWS 25
+
+  if (ps->reports % (ROWS - 3) == (ROWS - 4))
+    rheader (ps);
+
+  fflush (ps->out);
+}
+
+static int
+bcp_queue_is_empty (PS * ps)
+{
+  if (ps->ttail != ps->thead)
+    return 0;
+
+  if (ps->ttail2 != ps->thead)
+    return 0;
+
+#ifndef NADC
+  if (ps->ttailado != ps->thead)
+    return 0;
+#endif
+
+  return 1;
+}
+
+static int
+satisfied (PS * ps)
+{
+  assert (!ps->mtcls);
+  assert (!ps->failed_assumption);
+  if (ps->alstail < ps->alshead)
+    return 0;
+  assert (!ps->conflict);
+  assert (bcp_queue_is_empty (ps));
+  return ps->thead == ps->trail + ps->max_var;	/* all assigned */
+}
+
+static void
+vrescore (PS * ps)
+{
+  Rnk *p, *eor = ps->rnks + ps->max_var;
+  for (p = ps->rnks + 1; p <= eor; p++)
+    if (p->score != INFFLT)
+      p->score = mulflt (p->score, ps->ilvinc);
+  ps->vinc = mulflt (ps->vinc, ps->ilvinc);;
+#ifdef VISCORES
+  ps->nvinc = mulflt (ps->nvinc, ps->lscore);;
+#endif
+}
+
+static void
+inc_score (PS * ps, Var * v)
+{
+  Flt score;
+  Rnk *r;
+
+#ifndef NFL
+  if (ps->simplifying)
+    return;
+#endif
+
+  if (!v->level)
+    return;
+
+  if (v->internal)
+    return;
+
+  r = VAR2RNK (v);
+  score = r->score;
+
+  assert (score != INFFLT);
+
+  score = addflt (score, ps->vinc);
+  assert (score < INFFLT);
+  r->score = score;
+  if (r->pos > 0)
+    hup (ps, r);
+
+  if (score > ps->lscore)
+    vrescore (ps);
+}
+
+static void
+inc_activity (PS * ps, Cls * c)
+{
+  Act *p;
+
+  if (!c->learned)
+    return;
+
+  if (c->size <= 2)
+    return;
+
+  p = CLS2ACT (c);
+  *p = addflt (*p, ps->cinc);
+}
+
+static unsigned
+hashlevel (unsigned l)
+{
+  return 1u << (l & 31);
+}
+
+static void
+push (PS * ps, Var * v)
+{
+  if (ps->dhead == ps->eod)
+    ENLARGE (ps->dfs, ps->dhead, ps->eod);
+
+  *ps->dhead++ = v;
+}
+
+static Var * 
+pop (PS * ps)
+{
+  assert (ps->dfs < ps->dhead);
+  return *--ps->dhead;
+}
+
+static void
+analyze (PS * ps)
+{
+  unsigned open, minlevel, siglevels, l, old, i, orig;
+  Lit *this, *other, **p, **q, **eol;
+  Var *v, *u, **m, *start, *uip;
+  Cls *c;
+
+  assert (ps->conflict);
+
+  assert (ps->ahead == ps->added);
+  assert (ps->mhead == ps->marked);
+  assert (ps->rhead == ps->resolved);
+
+  /* First, search for First UIP variable and mark all resolved variables.
+   * At the same time determine the minimum decision level involved.
+   * Increase activities of resolved variables.
+   */
+  q = ps->thead;
+  open = 0;
+  minlevel = ps->LEVEL;
+  siglevels = 0;
+  uip = 0;
+
+  c = ps->conflict;
+
+  for (;;)
+    {
+      add_antecedent (ps, c);
+      inc_activity (ps, c);
+      eol = end_of_lits (c);
+      for (p = c->lits; p < eol; p++)
+	{
+	  other = *p;
+
+	  if (other->val == TRUE)
+	    continue;
+
+	  assert (other->val == FALSE);
+
+	  u = LIT2VAR (other);
+	  if (u->mark)
+	    continue;
+	  
+	  u->mark = 1;
+	  inc_score (ps, u);
+	  use_var (ps, u);
+
+	  if (u->level == ps->LEVEL)
+	    {
+	      open++;
+	    }
+	  else 
+	    {
+	      push_var_as_marked (ps, u);
+
+	      if (u->level)
+		{
+		  /* The statistics counter 'nonminimizedllits' sums up the
+		   * number of literals that would be added if only the
+		   * 'first UIP' scheme for learned clauses would be used
+		   * and no clause minimization.
+		   */
+		  ps->nonminimizedllits++;
+
+		  if (u->level < minlevel)
+		    minlevel = u->level;
+
+		  siglevels |= hashlevel (u->level);
+		}
+	      else
+		{
+		  assert (!u->level);
+		  assert (u->reason);
+		}
+	    }
+	}
+
+      do
+	{
+	  if (q == ps->trail)
+	    {
+	      uip = 0;
+	      goto DONE_FIRST_UIP;
+	    }
+
+	  this = *--q;
+	  uip = LIT2VAR (this);
+	}
+      while (!uip->mark);
+
+      uip->mark = 0;
+
+      c = var2reason (ps, uip);
+#ifdef NO_BINARY_CLAUSES
+      if (c == &ps->impl)
+	resetimpl (ps);
+#endif
+     open--;
+     if ((!open && ps->LEVEL) || !c)
+	break;
+
+     assert (c);
+    }
+
+DONE_FIRST_UIP:
+
+  if (uip)
+    {
+      assert (ps->LEVEL);
+      this = VAR2LIT (uip);
+      this += (this->val == TRUE);
+      ps->nonminimizedllits++;
+      ps->minimizedllits++;
+      add_lit (ps, this);
+#ifdef STATS
+      if (uip->reason)
+	ps->uips++;
+#endif
+    }
+  else
+    assert (!ps->LEVEL);
+
+  /* Second, try to mark more intermediate variables, with the goal to
+   * minimize the conflict clause.  This is a DFS from already marked
+   * variables backward through the implication graph.  It tries to reach
+   * other marked variables.  If the search reaches an unmarked decision
+   * variable or a variable assigned below the minimum level of variables in
+   * the first uip learned clause or a level on which no variable has been
+   * marked, then the variable from which the DFS is started is not
+   * redundant.  Otherwise the start variable is redundant and will
+   * eventually be removed from the learned clause in step 4.  We initially
+   * implemented BFS, but then profiling revelead that this step is a bottle
+   * neck for certain incremental applications.  After switching to DFS this
+   * hot spot went away.
+   */
+  orig = ps->mhead - ps->marked;
+  for (i = 0; i < orig; i++)
+    {
+      start = ps->marked[i];
+
+      assert (start->mark);
+      assert (start != uip);
+      assert (start->level < ps->LEVEL);
+
+      if (!start->reason)
+	continue;
+
+      old = ps->mhead - ps->marked;
+      assert (ps->dhead == ps->dfs);
+      push (ps, start);
+
+      while (ps->dhead > ps->dfs)
+	{
+	  u = pop (ps);
+	  assert (u->mark);
+
+	  c = var2reason (ps, u);
+#ifdef NO_BINARY_CLAUSES
+	  if (c == &ps->impl)
+	    resetimpl (ps);
+#endif
+	  if (!c || 
+	      ((l = u->level) && 
+	       (l < minlevel || ((hashlevel (l) & ~siglevels)))))
+	    {
+	      while (ps->mhead > ps->marked + old)	/* reset all marked */
+		(*--ps->mhead)->mark = 0;
+
+	      ps->dhead = ps->dfs;		/* and DFS stack */
+	      break;
+	    }
+
+	  eol = end_of_lits (c);
+	  for (p = c->lits; p < eol; p++)
+	    {
+	      v = LIT2VAR (*p);
+	      if (v->mark)
+		continue;
+
+	      mark_var (ps, v);
+	      push (ps, v);
+	    }
+	}
+    }
+
+  for (m = ps->marked; m < ps->mhead; m++)
+    {
+      v = *m;
+
+      assert (v->mark);
+      assert (!v->resolved);
+
+      use_var (ps, v);
+
+      c = var2reason (ps, v);
+      if (!c)
+	continue;
+
+#ifdef NO_BINARY_CLAUSES
+      if (c == &ps->impl)
+	resetimpl (ps);
+#endif
+      eol = end_of_lits (c);
+      for (p = c->lits; p < eol; p++)
+	{
+	  other = *p;
+
+	  u = LIT2VAR (other);
+	  if (!u->level)
+	    continue;
+
+	  if (!u->mark)		/* 'MARKTEST' */
+	    break;
+	}
+
+      if (p != eol)
+	continue;
+
+      add_antecedent (ps, c);
+      v->resolved = 1;
+    }
+
+  for (m = ps->marked; m < ps->mhead; m++)
+    {
+      v = *m;
+
+      assert (v->mark);
+      v->mark = 0;
+
+      if (v->resolved)
+	{
+	  v->resolved = 0;
+	  continue;
+	}
+
+      this = VAR2LIT (v);
+      if (this->val == TRUE)
+	this++;			/* actually NOTLIT */
+
+      add_lit (ps, this);
+      ps->minimizedllits++;
+    }
+
+  assert (ps->ahead <= ps->eoa);
+  assert (ps->rhead <= ps->eor);
+
+  ps->mhead = ps->marked;
+}
+
+static void
+fanalyze (PS * ps)
+{
+  Lit ** eol, ** p, * lit;
+  Cls * c, * reason;
+  Var * v, * u;
+  int next;
+
+#ifndef RCODE
+  double start = picosat_time_stamp ();
+#endif
+
+  assert (ps->failed_assumption);
+  assert (ps->failed_assumption->val == FALSE);
+
+  v = LIT2VAR (ps->failed_assumption);
+  reason = var2reason (ps, v);
+  if (!reason) return;
+#ifdef NO_BINARY_CLAUSES
+  if (reason == &ps->impl)
+    resetimpl (ps);
+#endif
+
+  eol = end_of_lits (reason);
+  for (p = reason->lits; p != eol; p++)
+    {
+      lit = *p;
+      u = LIT2VAR (lit);
+      if (u == v) continue;
+      if (u->reason) break;
+    }
+  if (p == eol) return;
+
+  assert (ps->ahead == ps->added);
+  assert (ps->mhead == ps->marked);
+  assert (ps->rhead == ps->resolved);
+
+  next = 0;
+  mark_var (ps, v);
+  add_lit (ps, NOTLIT (ps->failed_assumption));
+
+  do
+    {
+      v = ps->marked[next++];
+      use_var (ps, v);
+      if (v->reason)
+	{
+	  reason = var2reason (ps, v);
+#ifdef NO_BINARY_CLAUSES
+	  if (reason == &ps->impl)
+	    resetimpl (ps);
+#endif
+	  add_antecedent (ps, reason);
+	  eol = end_of_lits (reason);
+	  for (p = reason->lits; p != eol; p++)
+	    {
+	      lit = *p;
+	      u = LIT2VAR (lit);
+	      if (u == v) continue;
+	      if (u->mark) continue;
+	      mark_var (ps, u);
+	    }
+	}
+      else
+	{
+	  lit = VAR2LIT (v);
+	  if (lit->val == TRUE) lit = NOTLIT (lit);
+	  add_lit (ps, lit);
+	}
+    } 
+  while (ps->marked + next < ps->mhead);
+
+  c = add_simplified_clause (ps, 1);
+  v = LIT2VAR (ps->failed_assumption);
+  reason = v->reason;
+#ifdef NO_BINARY_CLAUSES
+  if (!ISLITREASON (reason))
+#endif
+    {
+      assert (reason->locked);
+      reason->locked = 0;
+      if (reason->learned && reason->size > 2)
+	{
+	  assert (ps->llocked > 0);
+	  ps->llocked--;
+	}
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  if (c == &ps->impl)
+    {
+      c = impl2reason (ps, NOTLIT (ps->failed_assumption));
+    }
+  else
+#endif
+    {
+      assert (c->learned);
+      assert (!c->locked);
+      c->locked = 1;
+      if (c->size > 2)
+	{
+	  ps->llocked++;
+	  assert (ps->llocked > 0);
+	}
+    }
+
+  v->reason = c;
+
+  while (ps->mhead > ps->marked)
+    (*--ps->mhead)->mark = 0;
+
+  if (ps->verbosity)
+     fprintf (ps->out, "%sfanalyze took %.1f seconds\n", 
+	     ps->prefix, picosat_time_stamp () - start);
+}
+
+/* Propagate assignment of 'this' to 'FALSE' by visiting all binary clauses in
+ * which 'this' occurs.
+ */
+inline static void
+prop2 (PS * ps, Lit * this)
+{
+#ifdef NO_BINARY_CLAUSES
+  Lit ** l, ** start;
+  Ltk * lstk;
+#else
+  Cls * c, ** p;
+  Cls * next;
+#endif
+  Lit * other;
+  Val tmp;
+
+  assert (this->val == FALSE);
+
+#ifdef NO_BINARY_CLAUSES
+  lstk = LIT2IMPLS (this);
+  start = lstk->start;
+  l = start + lstk->count;
+  while (l != start)
+    {
+      /* The counter 'visits' is the number of clauses that are
+       * visited during propagations of assignments.
+       */
+      ps->visits++;
+#ifdef STATS
+      ps->bvisits++;
+#endif
+      other = *--l;
+      tmp = other->val;
+
+      if (tmp == TRUE)
+	{
+#ifdef STATS
+	  ps->othertrue++;
+	  ps->othertrue2++;
+	  if (LIT2VAR (other)->level < ps->LEVEL)
+	    ps->othertrue2u++;
+#endif
+	  continue;
+	}
+
+      if (tmp != FALSE)
+	{
+	  assign_forced (ps, other, LIT2REASON (NOTLIT(this)));
+	  continue;
+	}
+
+      if (ps->conflict == &ps->cimpl)
+	resetcimpl (ps);
+      ps->conflict = setcimpl (ps, this, other);
+    }
+#else
+  /* Traverse all binary clauses with 'this'.  Head/Tail pointers for binary
+   * clauses do not have to be modified here.
+   */
+  p = LIT2IMPLS (this);
+  for (c = *p; c; c = next)
+    {
+      ps->visits++;
+#ifdef STATS
+      ps->bvisits++;
+#endif
+      assert (!c->collect);
+#ifdef TRACE
+      assert (!c->collected);
+#endif
+      assert (c->size == 2);
+      
+      other = c->lits[0];
+      if (other == this)
+	{
+	  next = c->next[0];
+	  other = c->lits[1];
+	}
+      else
+	next = c->next[1];
+
+      tmp = other->val;
+
+      if (tmp == TRUE)
+	{
+#ifdef STATS
+	  ps->othertrue++;
+	  ps->othertrue2++;
+	  if (LIT2VAR (other)->level < ps->LEVEL)
+	    ps->othertrue2u++;
+#endif
+	  continue;
+	}
+
+      if (tmp == FALSE)
+	ps->conflict = c;
+      else
+	assign_forced (ps, other, c);	/* unit clause */
+    }
+#endif /* !defined(NO_BINARY_CLAUSES) */
+}
+
+#ifndef NDSC
+static int
+should_disconnect_head_tail (PS * ps, Lit * lit)
+{
+  unsigned litlevel;
+  Var * v;
+
+  assert (lit->val == TRUE);
+
+  v = LIT2VAR (lit);
+  litlevel = v->level;
+
+  if (!litlevel)
+    return 1;
+
+#ifndef NFL
+  if (ps->simplifying)
+    return 0;
+#endif
+
+  return litlevel < ps->LEVEL;
+}
+#endif
+
+inline static void
+propl (PS * ps, Lit * this)
+{
+  Lit **l, *other, *prev, *new_lit, **eol;
+  Cls *next, **htp_ptr, **new_htp_ptr;
+  Cls *c;
+#ifdef STATS
+  unsigned size;
+#endif
+
+  htp_ptr = LIT2HTPS (this);
+  assert (this->val == FALSE);
+
+  /* Traverse all non binary clauses with 'this'.  Head/Tail pointers are
+   * updated as well.
+   */
+  for (c = *htp_ptr; c; c = next)
+    {
+      ps->visits++;
+#ifdef STATS
+      size = c->size;
+      assert (size >= 3);
+      ps->traversals++;	/* other is dereferenced at least */
+
+      if (size == 3)
+	ps->tvisits++;
+      else if (size >= 4)
+	{
+	  ps->lvisits++;
+	  ps->ltraversals++;
+	}
+#endif
+#ifdef TRACE
+      assert (!c->collected);
+#endif
+      assert (c->size > 0);
+
+      other = c->lits[0];
+      if (other != this)
+	{
+	  assert (c->size != 1);
+	  c->lits[0] = this;
+	  c->lits[1] = other;
+	  next = c->next[1];
+	  c->next[1] = c->next[0];
+	  c->next[0] = next;
+	}
+      else if (c->size == 1)	/* With assumptions we need to
+	                         * traverse unit clauses as well.
+			         */
+	{
+	  assert (!ps->conflict);
+	  ps->conflict = c;
+	  break;
+	}
+      else
+	{
+	  assert (other == this && c->size > 1);
+	  other = c->lits[1];
+	  next = c->next[0];
+	}
+      assert (other == c->lits[1]);
+      assert (this == c->lits[0]);
+      assert (next == c->next[0]);
+      assert (!c->collect);
+
+      if (other->val == TRUE)
+	{
+#ifdef STATS
+	  ps->othertrue++;
+	  ps->othertruel++;
+#endif
+#ifndef NDSC
+	  if (should_disconnect_head_tail (ps, other))
+	    {
+	      new_htp_ptr = LIT2DHTPS (other);
+	      c->next[0] = *new_htp_ptr;
+	      *new_htp_ptr = c;
+#ifdef STATS
+	      ps->othertruelu++;
+#endif
+	      *htp_ptr = next;
+	      continue;
+	    }
+#endif
+	  htp_ptr = c->next;
+	  continue;
+	}
+
+      l = c->lits + 1;
+      eol = (Lit**) c->lits + c->size;
+      prev = this;
+
+      while (++l != eol)
+	{
+#ifdef STATS
+	  if (size >= 3)
+	    {
+	      ps->traversals++;
+	      if (size > 3)
+		ps->ltraversals++;
+	    }
+#endif
+	  new_lit = *l;
+	  *l = prev;
+	  prev = new_lit;
+	  if (new_lit->val != FALSE) break;
+	}
+
+      if (l == eol)
+	{
+	  while (l > c->lits + 2) 
+	    {
+	      new_lit = *--l;
+	      *l = prev;
+	      prev = new_lit;
+	    }
+	  assert (c->lits[0] == this);
+
+	  assert (other == c->lits[1]);
+	  if (other->val == FALSE)	/* found conflict */
+	    {
+	      assert (!ps->conflict);
+	      ps->conflict = c;
+	      return;
+	    }
+
+	  assign_forced (ps, other, c);		/* unit clause */
+	  htp_ptr = c->next;
+	}
+      else
+	{
+	  assert (new_lit->val == TRUE || new_lit->val == UNDEF);
+	  c->lits[0] = new_lit;
+	  // *l = this;
+	  new_htp_ptr = LIT2HTPS (new_lit);
+	  c->next[0] = *new_htp_ptr;
+	  *new_htp_ptr = c;
+	  *htp_ptr = next;
+	}
+    }
+}
+
+#ifndef NADC
+
+static unsigned primes[] = { 996293, 330643, 753947, 500873 };
+
+#define PRIMES ((sizeof primes)/sizeof *primes)
+
+static unsigned
+hash_ado (PS * ps, Lit ** ado, unsigned salt)
+{
+  unsigned i, res, tmp;
+  Lit ** p, * lit;
+
+  assert (salt < PRIMES);
+
+  i = salt;
+  res = 0;
+
+  for (p = ado; (lit = *p); p++)
+    {
+      assert (lit->val);
+
+      tmp = res >> 31;
+      res <<= 1;
+
+      if (lit->val > 0)
+	res |= 1;
+
+      assert (i < PRIMES);
+      res *= primes[i++];
+      if (i == PRIMES)
+	i = 0;
+
+      res += tmp;
+    }
+
+  return res & (ps->szadotab - 1);
+}
+
+static unsigned
+cmp_ado (Lit ** a, Lit ** b)
+{
+  Lit ** p, ** q, * l, * k;
+  int res;
+
+  for (p = a, q = b; (l = *p); p++, q++)
+    {
+      k = *q;
+      assert (k);
+      if ((res = (l->val - k->val)))
+	return res;
+    }
+
+  assert (!*q);
+
+  return 0;
+}
+
+static Lit ***
+find_ado (PS * ps, Lit ** ado)
+{
+  Lit *** res, ** other;
+  unsigned pos, delta;
+
+  pos = hash_ado (ps, ado, 0);
+  assert (pos < ps->szadotab);
+  res = ps->adotab + pos;
+
+  other = *res;
+  if (!other || !cmp_ado (other, ado))
+    return res;
+
+  delta = hash_ado (ps, ado, 1);
+  if (!(delta & 1))
+    delta++;
+
+  assert (delta & 1);
+  assert (delta < ps->szadotab);
+
+  for (;;)
+    {
+      pos += delta;
+      if (pos >= ps->szadotab)
+	pos -= ps->szadotab;
+
+      assert (pos < ps->szadotab);
+      res = ps->adotab + pos;
+      other = *res;
+      if (!other || !cmp_ado (other, ado))
+	return res;
+    }
+}
+
+static void
+enlarge_adotab (PS * ps)
+{
+  /* TODO make this generic */
+
+  ABORTIF (ps->szadotab, 
+           "internal: all different objects table needs larger initial size");
+  assert (!ps->nadotab);
+  ps->szadotab = 10000;
+  NEWN (ps->adotab, ps->szadotab);
+  CLRN (ps->adotab, ps->szadotab);
+}
+
+static int
+propado (PS * ps, Var * v)
+{
+  Lit ** p, ** q, *** adotabpos, **ado, * lit;
+  Var * u;
+
+  if (ps->LEVEL && ps->adodisabled)
+    return 1;
+
+  assert (!ps->conflict);
+  assert (!ps->adoconflict);
+  assert (VAR2LIT (v)->val != UNDEF);
+  assert (!v->adotabpos);
+
+  if (!v->ado)
+    return 1;
+
+  assert (v->inado);
+
+  for (p = v->ado; (lit = *p); p++)
+    if (lit->val == UNDEF)
+      {
+	u = LIT2VAR (lit);
+	assert (!u->ado);
+	u->ado = v->ado;
+	v->ado = 0;
+
+	return 1;
+      }
+
+  if (4 * ps->nadotab >= 3 * ps->szadotab)	/* at least 75% filled */
+    enlarge_adotab (ps);
+
+  adotabpos = find_ado (ps, v->ado);
+  ado = *adotabpos;
+
+  if (!ado)
+    {
+      ps->nadotab++;
+      v->adotabpos = adotabpos;
+      *adotabpos = v->ado;
+      return 1;
+    }
+
+  assert (ado != v->ado);
+
+  ps->adoconflict = new_clause (ps, 2 * llength (ado), 1);
+  q = ps->adoconflict->lits;
+
+  for (p = ado; (lit = *p); p++)
+    *q++ = lit->val == FALSE ? lit : NOTLIT (lit);
+
+  for (p = v->ado; (lit = *p); p++)
+    *q++ = lit->val == FALSE ? lit : NOTLIT (lit);
+
+  assert (q == ENDOFCLS (ps->adoconflict));
+  ps->conflict = ps->adoconflict;
+  ps->adoconflicts++;
+  return 0;
+}
+
+#endif
+
+static void
+bcp (PS * ps)
+{
+  int props = 0;
+  assert (!ps->conflict);
+
+  if (ps->mtcls)
+    return;
+
+  for (;;)
+    {
+      if (ps->ttail2 < ps->thead)	/* prioritize implications */
+	{
+	  props++;
+	  prop2 (ps, NOTLIT (*ps->ttail2++));
+	}
+      else if (ps->ttail < ps->thead)	/* unit clauses or clauses with length > 2 */
+	{
+	  if (ps->conflict) break;
+	  propl (ps, NOTLIT (*ps->ttail++));
+	  if (ps->conflict) break;
+	}
+#ifndef NADC
+      else if (ps->ttailado < ps->thead)
+	{
+	  if (ps->conflict) break;
+	  propado (ps, LIT2VAR (*ps->ttailado++));
+	  if (ps->conflict) break;
+	}
+#endif
+      else
+	break;		/* all assignments propagated, so break */
+    }
+
+  ps->propagations += props;
+}
+
+static unsigned
+drive (PS * ps)
+{
+  unsigned res, vlevel;
+  Lit **p;
+  Var *v;
+
+  res = 0;
+  for (p = ps->added; p < ps->ahead; p++)
+    {
+      v = LIT2VAR (*p);
+      vlevel = v->level;
+      assert (vlevel <= ps->LEVEL);
+      if (vlevel < ps->LEVEL && vlevel > res)
+	res = vlevel;
+    }
+
+  return res;
+}
+
+#ifdef VISCORES
+
+static void
+viscores (PS * ps)
+{
+  Rnk *p, *eor = ps->rnks + ps->max_var;
+  char name[100], cmd[200];
+  FILE * data;
+  Flt s;
+  int i;
+
+  for (p = ps->rnks + 1; p <= ps->eor; p++)
+    {
+      s = p->score;
+      if (s == INFFLT)
+	continue;
+      s = mulflt (s, ps->nvinc);
+      assert (flt2double (s) <= 1.0);
+    }
+
+  sprintf (name, "/tmp/picosat-viscores/data/%08u", ps->conflicts);
+  sprintf (cmd, "sort -n|nl>%s", name);
+
+  data = popen (cmd, "w");
+  for (p = ps->rnks + 1; p <= ps->eor; p++)
+    {
+      s = p->score;
+      if (s == INFFLT)
+	continue;
+      s = mulflt (s, ps->nvinc);
+      fprintf (data, "%lf %d\n", 100.0 * flt2double (s), (int)(p - ps->rnks));
+    }
+  fflush (data);
+  pclose (data);
+
+  for (i = 0; i < 8; i++)
+    {
+      sprintf (cmd, "awk '$3%%8==%d' %s>%s.%d", i, name, name, i);
+      system (cmd);
+    }
+
+  fprintf (ps->fviscores, "set title \"%u\"\n", ps->conflicts);
+  fprintf (ps->fviscores, "plot [0:%u] 0, 100 * (1 - 1/1.1), 100", ps->max_var);
+
+  for (i = 0; i < 8; i++)
+    fprintf (ps->fviscores, 
+             ", \"%s.%d\" using 1:2:3 with labels tc lt %d", 
+	     name, i, i + 1);
+
+  fputc ('\n', ps->fviscores);
+  fflush (ps->fviscores);
+#ifndef WRITEGIF
+  usleep (50000);		/* refresh rate of 20 Hz */
+#endif
+}
+
+#endif
+
+static void
+crescore (PS * ps)
+{
+  Cls **p, *c;
+  Act *a;
+  Flt factor;
+  int l = log2flt (ps->cinc);
+  assert (l > 0);
+  factor = base2flt (1, -l);
+
+  for (p = ps->lclauses; p != ps->lhead; p++)
+    {
+      c = *p;
+
+      if (!c)
+	continue;
+
+#ifdef TRACE
+      if (c->collected)
+	continue;
+#endif
+      assert (c->learned);
+
+      if (c->size <= 2)
+	continue;
+
+      a = CLS2ACT (c);
+      *a = mulflt (*a, factor);
+    }
+
+  ps->cinc = mulflt (ps->cinc, factor);
+}
+
+static void
+inc_vinc (PS * ps)
+{
+#ifdef VISCORES
+  ps->nvinc = mulflt (ps->nvinc, ps->fvinc);
+#endif
+  ps->vinc = mulflt (ps->vinc, ps->ifvinc);
+}
+
+inline static void
+inc_max_var (PS * ps)
+{
+  Lit *lit;
+  Rnk *r;
+  Var *v;
+
+  assert (ps->max_var < ps->size_vars);
+
+  if (ps->max_var + 1 == ps->size_vars)
+    enlarge (ps, ps->size_vars + 2*(ps->size_vars + 3) / 4); /* +25% */
+
+  ps->max_var++;			/* new index of variable */
+  assert (ps->max_var);			/* no unsigned overflow */
+
+  assert (ps->max_var < ps->size_vars);
+
+  lit = ps->lits + 2 * ps->max_var;
+  lit[0].val = lit[1].val = UNDEF;
+
+  memset (ps->htps + 2 * ps->max_var, 0, 2 * sizeof *ps->htps);
+#ifndef NDSC
+  memset (ps->dhtps + 2 * ps->max_var, 0, 2 * sizeof *ps->dhtps);
+#endif
+  memset (ps->impls + 2 * ps->max_var, 0, 2 * sizeof *ps->impls);
+  memset (ps->jwh + 2 * ps->max_var, 0, 2 * sizeof *ps->jwh);
+
+  v = ps->vars + ps->max_var;		/* initialize variable components */
+  CLR (v);
+
+  r = ps->rnks + ps->max_var;		/* initialize rank */
+  CLR (r);
+
+  hpush (ps, r);
+}
+
+static void
+force (PS * ps, Cls * c)
+{
+  Lit ** p, ** eol, * lit, * forced;
+  Cls * reason;
+
+  forced = 0;
+  reason = c;
+
+  eol = end_of_lits (c);
+  for (p = c->lits; p < eol; p++)
+    {
+      lit = *p;
+      if (lit->val == UNDEF)
+	{
+	  assert (!forced);
+	  forced = lit;
+#ifdef NO_BINARY_CLAUSES
+	  if (c == &ps->impl)
+	    reason = LIT2REASON (NOTLIT (p[p == c->lits ? 1 : -1]));
+#endif
+	}
+      else
+	assert (lit->val == FALSE);
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  if (c == &ps->impl)
+    resetimpl (ps);
+#endif
+  if (!forced)
+    return;
+
+  assign_forced (ps, forced, reason);
+}
+
+static void
+inc_lreduce (PS * ps)
+{
+#ifdef STATS
+  ps->inclreduces++;
+#endif
+  ps->lreduce *= FREDUCE;
+  ps->lreduce /= 100;
+  report (ps, 1, '+');
+}
+
+static void
+backtrack (PS * ps)
+{
+  unsigned new_level;
+  Cls * c;
+
+  ps->conflicts++;
+  LOG ( fprintf (ps->out, "%sconflict ", ps->prefix); dumpclsnl (ps, ps->conflict));
+
+  analyze (ps);
+  new_level = drive (ps);
+  // TODO: why not? assert (new_level != 1  || (ps->ahead - ps->added) == 2);
+  c = add_simplified_clause (ps, 1);
+  undo (ps, new_level);
+  force (ps, c);
+
+  if (
+#ifndef NFL
+      !ps->simplifying && 
+#endif
+      !--ps->lreduceadjustcnt)
+    {
+      /* With FREDUCE==110 and FREDADJ=121 we stir 'lreduce' to be
+       * proportional to 'sqrt(conflicts)'.  In earlier version we actually
+       * used  'FREDADJ=150', which results in 'lreduce' to approximate
+       * 'conflicts^(log(1.1)/log(1.5))' which is close to the fourth root
+       * of 'conflicts', since log(1.1)/log(1.5)=0.235 (as observed by
+       * Donald Knuth). The square root is the same we get by a Glucose
+       * style increase, which simply adds a constant at every reduction.
+       * This would be way simpler to implement but for now we keep the more
+       * complicated code using the adjust increments and counters.
+       */
+      ps->lreduceadjustinc *= FREDADJ; ps->lreduceadjustinc /= 100; ps->lreduceadjustcnt
+      = ps->lreduceadjustinc;
+      inc_lreduce (ps);
+    }
+
+  if (ps->verbosity >= 4 && !(ps->conflicts % 1000))
+    report (ps, 4, 'C');
+}
+
+static void
+inc_cinc (PS * ps)
+{
+  ps->cinc = mulflt (ps->cinc, ps->fcinc);
+  if (ps->lcinc < ps->cinc)
+    crescore (ps);
+}
+
+static void
+incincs (PS * ps)
+{
+  inc_vinc (ps);
+  inc_cinc (ps);
+#ifdef VISCORES
+  viscores (ps);
+#endif
+}
+
+static void
+disconnect_clause (PS * ps, Cls * c)
+{
+  assert (c->connected);
+
+  if (c->size > 2)
+    {
+      if (c->learned)
+	{
+	  assert (ps->nlclauses > 0);
+	  ps->nlclauses--;
+
+	  assert (ps->llits >= c->size);
+	  ps->llits -= c->size;
+	}
+      else
+	{
+	  assert (ps->noclauses > 0);
+	  ps->noclauses--;
+
+	  assert (ps->olits >= c->size);
+	  ps->olits -= c->size;
+	}
+    }
+
+#ifndef NDEBUG
+  c->connected = 0;
+#endif
+}
+
+static int
+clause_is_toplevel_satisfied (PS * ps, Cls * c)
+{
+  Lit *lit, **p, **eol = end_of_lits (c);
+  Var *v;
+
+  for (p = c->lits; p < eol; p++)
+    {
+      lit = *p;
+      if (lit->val == TRUE)
+	{
+	  v = LIT2VAR (lit);
+	  if (!v->level)
+	    return 1;
+	}
+    }
+
+  return 0;
+}
+
+static int
+collect_clause (PS * ps, Cls * c)
+{
+  assert (c->collect);
+  c->collect = 0;
+
+#ifdef TRACE
+  assert (!c->collected);
+  c->collected = 1;
+#endif
+  disconnect_clause (ps, c);
+
+#ifdef TRACE
+  if (ps->trace && (!c->learned || c->used))
+    return 0;
+#endif
+  delete_clause (ps, c);
+
+  return 1;
+}
+
+static size_t
+collect_clauses (PS * ps)
+{
+  Cls *c, **p, **q, * next;
+  Lit * lit, * eol;
+  size_t res;
+  int i;
+
+  res = ps->current_bytes;
+
+  eol = ps->lits + 2 * ps->max_var + 1;
+  for (lit = ps->lits + 2; lit <= eol; lit++)
+    {
+      for (i = 0; i <= 1; i++)
+	{
+	  if (i)
+	    {
+#ifdef NO_BINARY_CLAUSES
+	      Ltk * lstk = LIT2IMPLS (lit);
+	      Lit ** r, ** s;
+	      r = lstk->start;
+	      if (lit->val != TRUE || LIT2VAR (lit)->level)
+		for (s = r; s < lstk->start + lstk->count; s++)
+		  {
+		    Lit * other = *s;
+		    Var *v = LIT2VAR (other);
+		    if (v->level ||
+		        other->val != TRUE)
+		      *r++ = other;
+		  }
+	      lstk->count = r - lstk->start;
+	      continue;
+#else
+	      p = LIT2IMPLS (lit);
+#endif
+	    }
+	  else
+	    p = LIT2HTPS (lit);
+
+	  for (c = *p; c; c = next)
+	    {
+	      q = c->next;
+	      if (c->lits[0] != lit)
+		q++;
+
+	      next = *q;
+	      if (c->collect)
+		*p = next;
+	      else
+		p = q;
+	    }
+	}
+    }
+
+#ifndef NDSC
+  for (lit = ps->lits + 2; lit <= eol; lit++)
+    {
+      p = LIT2DHTPS (lit); 
+      while ((c = *p))
+	{
+	  Lit * other = c->lits[0];
+	  if (other == lit)
+	    {
+	      q = c->next + 1;
+	    }
+	  else
+	    {
+	      assert (c->lits[1] == lit);
+	      q = c->next;
+	    }
+
+	  if (c->collect)
+	    *p = *q;
+	  else
+	    p = q;
+	}
+    }
+#endif
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+
+      if (!c)
+	continue;
+
+      if (!c->collect)
+	continue;
+
+      if (collect_clause (ps, c))
+	*p = 0;
+    }
+
+#ifdef TRACE
+  if (!ps->trace)
+#endif
+    {
+      q = ps->oclauses;
+      for (p = q; p < ps->ohead; p++)
+	if ((c = *p))
+	  *q++ = c;
+      ps->ohead = q;
+
+      q = ps->lclauses;
+      for (p = q; p < ps->lhead; p++)
+	if ((c = *p))
+	  *q++ = c;
+      ps->lhead = q;
+    }
+
+  assert (ps->current_bytes <= res);
+  res -= ps->current_bytes;
+  ps->recycled += res;
+
+  LOG ( fprintf (ps->out, "%scollected %ld bytes\n", ps->prefix, (long)res));
+
+  return res;
+}
+
+static int
+need_to_reduce (PS * ps)
+{
+  return ps->nlclauses >= reduce_limit_on_lclauses (ps);
+}
+
+#ifdef NLUBY
+
+static void
+inc_drestart (PS * ps)
+{
+  ps->drestart *= FRESTART;
+  ps->drestart /= 100;
+
+  if (ps->drestart >= MAXRESTART)
+    ps->drestart = MAXRESTART;
+}
+
+static void
+inc_ddrestart (PS * ps)
+{
+  ps->ddrestart *= FRESTART;
+  ps->ddrestart /= 100;
+
+  if (ps->ddrestart >= MAXRESTART)
+    ps->ddrestart = MAXRESTART;
+}
+
+#else
+
+static unsigned
+luby (unsigned i)
+{
+  unsigned k;
+  for (k = 1; k < 32; k++)
+    if (i == (1u << k) - 1)
+      return 1u << (k - 1);
+
+  for (k = 1;; k++)
+    if ((1u << (k - 1)) <= i && i < (1u << k) - 1)
+      return luby (i - (1u << (k-1)) + 1);
+}
+
+#endif
+
+#ifndef NLUBY
+static void
+inc_lrestart (PS * ps, int skip)
+{
+  unsigned delta;
+
+  delta = 100 * luby (++ps->lubycnt);
+  ps->lrestart = ps->conflicts + delta;
+
+  if (ps->waslubymaxdelta)
+    report (ps, 1, skip ? 'N' : 'R');
+  else
+    report (ps, 2, skip ? 'n' : 'r');
+
+  if (delta > ps->lubymaxdelta)
+    {
+      ps->lubymaxdelta = delta;
+      ps->waslubymaxdelta = 1;
+    }
+  else
+    ps->waslubymaxdelta = 0;
+}
+#endif
+
+static void
+init_restart (PS * ps)
+{
+#ifdef NLUBY
+  /* TODO: why is it better in incremental usage to have smaller initial
+   * outer restart interval?
+   */
+  ps->ddrestart = ps->calls > 1 ? MINRESTART : 1000;
+  ps->drestart = MINRESTART;
+  ps->lrestart = ps->conflicts + ps->drestart;
+#else
+  ps->lubycnt = 0;
+  ps->lubymaxdelta = 0;
+  ps->waslubymaxdelta = 0;
+  inc_lrestart (ps, 0);
+#endif
+}
+
+static void
+restart (PS * ps)
+{
+  int skip; 
+#ifdef NLUBY
+  char kind;
+  int outer;
+ 
+  inc_drestart (ps);
+  outer = (ps->drestart >= ps->ddrestart);
+
+  if (outer)
+    skip = very_high_agility (ps);
+  else
+    skip = high_agility (ps);
+#else
+  skip = medium_agility (ps);
+#endif
+
+#ifdef STATS
+  if (skip)
+    ps->skippedrestarts++;
+#endif
+
+  assert (ps->conflicts >= ps->lrestart);
+
+  if (!skip)
+    {
+      ps->restarts++;
+      assert (ps->LEVEL > 1);
+      LOG ( fprintf (ps->out, "%srestart %u\n", ps->prefix, ps->restarts));
+      undo (ps, 0);
+    }
+
+#ifdef NLUBY
+  if (outer)
+    {
+      kind = skip ? 'N' : 'R';
+      inc_ddrestart (ps);
+      ps->drestart = MINRESTART;
+    }
+  else  if (skip)
+    {
+      kind = 'n';
+    }
+  else
+    {
+      kind = 'r';
+    }
+
+  assert (ps->drestart <= MAXRESTART);
+  ps->lrestart = ps->conflicts + ps->drestart;
+  assert (ps->lrestart > ps->conflicts);
+
+  report (outer ? 1 : 2, kind);
+#else
+  inc_lrestart (ps, skip);
+#endif
+}
+
+inline static void
+assign_decision (PS * ps, Lit * lit)
+{
+  assert (!ps->conflict);
+
+  ps->LEVEL++;
+
+  LOG ( fprintf (ps->out, "%snew level %u\n", ps->prefix, ps->LEVEL));
+  LOG ( fprintf (ps->out,
+		 "%sassign %d at level %d <= DECISION\n",
+		 ps->prefix, LIT2INT (lit), ps->LEVEL));
+
+  assign (ps, lit, 0);
+}
+
+#ifndef NFL
+
+static int
+lit_has_binary_clauses (PS * ps, Lit * lit)
+{
+#ifdef NO_BINARY_CLAUSES
+  Ltk* lstk = LIT2IMPLS (lit);
+  return lstk->count != 0;
+#else
+  return *LIT2IMPLS (lit) != 0;
+#endif
+}
+
+static void
+flbcp (PS * ps)
+{
+#ifdef STATS
+  unsigned long long propagaions_before_bcp = ps->propagations;
+#endif
+  bcp (ps);
+#ifdef STATS
+  ps->flprops += ps->propagations - propagaions_before_bcp;
+#endif
+}
+
+inline static int
+cmp_inverse_rnk (PS * ps, Rnk * a, Rnk * b)
+{
+  (void) ps;
+  return -cmp_rnk (a, b);
+}
+
+inline static Flt
+rnk2jwh (PS * ps, Rnk * r)
+{
+  Flt res, sum, pjwh, njwh;
+  Lit * plit, * nlit;
+
+  plit = RNK2LIT (r);
+  nlit = plit + 1;
+  
+  pjwh = *LIT2JWH (plit);
+  njwh = *LIT2JWH (nlit);
+
+  res = mulflt (pjwh, njwh);
+
+  sum = addflt (pjwh, njwh);
+  sum = mulflt (sum, base2flt (1, -10));
+  res = addflt (res, sum);
+
+  return res;
+}
+
+static int
+cmp_inverse_jwh_rnk (PS * ps, Rnk * r, Rnk * s)
+{
+  Flt a = rnk2jwh (ps, r);
+  Flt b = rnk2jwh (ps, s);
+  int res = cmpflt (a, b);
+
+  if (res)
+    return -res;
+
+  return cmp_inverse_rnk (ps, r, s);
+}
+
+static void
+faillits (PS * ps)
+{
+  unsigned i, j, old_trail_count, common, saved_count;
+  unsigned new_saved_size, oldladded = ps->ladded;
+  unsigned long long limit, delta;
+  Lit * lit, * other, * pivot;
+  Rnk * r, ** p, ** q;
+  int new_trail_count;
+  double started;
+
+  if (ps->plain)
+    return;
+
+  if (ps->heap + 1 >= ps->hhead)
+    return;
+
+  if (ps->propagations < ps->fllimit)
+    return;
+
+  sflush (ps);
+  started = ps->seconds;
+
+  ps->flcalls++;
+#ifdef STATSA
+  ps->flrounds++;
+#endif
+  delta = ps->propagations/10;
+  if (delta >= 100*1000*1000) delta = 100*1000*1000;
+  else if (delta <= 100*1000) delta = 100*1000;
+
+  limit = ps->propagations + delta;
+  ps->fllimit = ps->propagations;
+
+  assert (!ps->LEVEL);
+  assert (ps->simplifying);
+
+  if (ps->flcalls <= 1)
+    SORT (Rnk *, cmp_inverse_jwh_rnk, ps->heap + 1, ps->hhead - (ps->heap + 1));
+  else
+    SORT (Rnk *, cmp_inverse_rnk, ps->heap + 1, ps->hhead - (ps->heap + 1));
+
+  i = 1;		/* NOTE: heap starts at position '1' */
+
+  while (ps->propagations < limit)
+    {
+      if (ps->heap + i == ps->hhead)
+	{
+	  if (ps->ladded == oldladded)
+	    break;
+
+	  i = 1;
+#ifdef STATS
+	  ps->flrounds++;
+#endif
+	  oldladded = ps->ladded;
+	}
+
+      assert (ps->heap + i < ps->hhead);
+
+      r = ps->heap[i++];
+      lit = RNK2LIT (r);
+
+      if (lit->val)
+	continue;
+
+      if (!lit_has_binary_clauses (ps, NOTLIT (lit)))
+	{
+#ifdef STATS
+	  ps->flskipped++;
+#endif
+	  continue;
+	}
+
+#ifdef STATS
+      ps->fltried++;
+#endif
+      LOG ( fprintf (ps->out, "%strying %d as failed literal\n",
+	    ps->prefix, LIT2INT (lit)));
+
+      assign_decision (ps, lit);
+      old_trail_count = ps->thead - ps->trail;
+      flbcp (ps);
+
+      if (ps->conflict)
+	{
+EXPLICITLY_FAILED_LITERAL:
+	  LOG ( fprintf (ps->out, "%sfound explicitly failed literal %d\n",
+		ps->prefix, LIT2INT (lit)));
+
+	  ps->failedlits++;
+	  ps->efailedlits++;
+
+	  backtrack (ps);
+	  flbcp (ps);
+
+	  if (!ps->conflict)
+	    continue;
+
+CONTRADICTION:
+	  assert (!ps->LEVEL);
+	  backtrack (ps);
+	  assert (ps->mtcls);
+
+	  goto RETURN;
+	}
+
+      if (ps->propagations >= limit)
+	{
+	  undo (ps, 0);
+	  break;
+	}
+
+      lit = NOTLIT (lit);
+
+      if (!lit_has_binary_clauses (ps, NOTLIT (lit)))
+	{
+#ifdef STATS
+	  ps->flskipped++;
+#endif
+	  undo (ps, 0);
+	  continue;
+	}
+
+#ifdef STATS
+      ps->fltried++;
+#endif
+      LOG ( fprintf (ps->out, "%strying %d as failed literals\n",
+	    ps->prefix, LIT2INT (lit)));
+
+      new_trail_count = ps->thead - ps->trail;
+      saved_count = new_trail_count - old_trail_count;
+
+      if (saved_count > ps->saved_size)
+	{
+	  new_saved_size = ps->saved_size ? 2 * ps->saved_size : 1;
+	  while (saved_count > new_saved_size)
+	    new_saved_size *= 2;
+
+	  RESIZEN (ps->saved, ps->saved_size, new_saved_size);
+	  ps->saved_size = new_saved_size;
+	}
+
+      for (j = 0; j < saved_count; j++)
+	ps->saved[j] = ps->trail[old_trail_count + j];
+
+      undo (ps, 0);
+
+      assign_decision (ps, lit);
+      flbcp (ps);
+
+      if (ps->conflict)
+	goto EXPLICITLY_FAILED_LITERAL;
+
+      pivot = (ps->thead - ps->trail <= new_trail_count) ? lit : NOTLIT (lit);
+
+      common = 0;
+      for (j = 0; j < saved_count; j++)
+	if ((other = ps->saved[j])->val == TRUE)
+	  ps->saved[common++] = other;
+
+      undo (ps, 0);
+
+      LOG (if (common)
+	     fprintf (ps->out, 
+		      "%sfound %d literals implied by %d and %d\n",
+		      ps->prefix, common, 
+		      LIT2INT (NOTLIT (lit)), LIT2INT (lit)));
+
+#if 1 // set to zero to disable 'lifting'
+      for (j = 0; 
+	   j < common 
+	  /* TODO: For some Velev benchmarks, extracting the common implicit
+	   * failed literals took quite some time.  This needs to be fixed by
+	   * a dedicated analyzer.  Up to then we bound the number of
+	   * propagations in this loop as well.
+	   */
+	   && ps->propagations < limit + delta
+	   ; j++)
+	{
+	  other = ps->saved[j];
+
+	  if (other->val == TRUE)
+	    continue;
+
+	  assert (!other->val);
+
+	  LOG ( fprintf (ps->out, 
+			"%sforcing %d as forced implicitly failed literal\n",
+			ps->prefix, LIT2INT (other)));
+
+	  assert (pivot != NOTLIT (other));
+	  assert (pivot != other);
+
+	  assign_decision (ps, NOTLIT (other));
+	  flbcp (ps);
+
+	  assert (ps->LEVEL == 1);
+
+	  if (ps->conflict)
+	    {
+	      backtrack (ps);
+	      assert (!ps->LEVEL);
+	    }
+	  else
+	    {
+	      assign_decision (ps, pivot);
+	      flbcp (ps);
+
+	      backtrack (ps);
+
+	      if (ps->LEVEL)
+		{
+		  assert (ps->LEVEL == 1);
+
+		  flbcp (ps);
+
+		  if (ps->conflict)
+		    {
+		      backtrack (ps);
+		      assert (!ps->LEVEL);
+		    }
+		  else
+		    {
+		      assign_decision (ps, NOTLIT (pivot));
+		      flbcp (ps);
+		      backtrack (ps);
+
+		      if (ps->LEVEL)
+			{
+			  assert (ps->LEVEL == 1);
+			  flbcp (ps);
+
+			  if (!ps->conflict)
+			    {
+#ifdef STATS
+			      ps->floopsed++;
+#endif
+			      undo (ps, 0);
+			      continue;
+			    }
+
+			  backtrack (ps);
+			}
+
+		      assert (!ps->LEVEL);
+		    }
+
+		  assert (!ps->LEVEL);
+		}
+	    }
+	  assert (!ps->LEVEL);
+	  flbcp (ps);
+
+	  ps->failedlits++;
+	  ps->ifailedlits++;
+
+	  if (ps->conflict)
+	    goto CONTRADICTION;
+	}
+#endif
+    }
+
+  ps->fllimit += 9 * (ps->propagations - ps->fllimit);	/* 10% for failed literals */
+
+RETURN:
+
+  /* First flush top level assigned literals.  Those are prohibited from
+   * being pushed up the heap during 'faillits' since 'simplifying' is set.
+   */
+  assert (ps->heap < ps->hhead);
+  for (p = q = ps->heap + 1; p < ps->hhead; p++)
+    {
+      r = *p;
+      lit = RNK2LIT (r);
+      if (lit->val)
+       	r->pos = 0;
+      else
+	*q++ = r;
+    }
+
+  /* Then resort with respect to EVSIDS score and fix positions.
+   */
+  SORT (Rnk *, cmp_inverse_rnk, ps->heap + 1, ps->hhead - (ps->heap + 1));
+  for (p = ps->heap + 1; p < ps->hhead; p++)
+    (*p)->pos = p - ps->heap;
+
+  sflush (ps);
+  ps->flseconds += ps->seconds - started;
+}
+
+#endif
+
+static void
+simplify (PS * ps, int forced)
+{
+  Lit * lit, * notlit, ** t;
+  unsigned collect, delta;
+#ifdef STATS
+  size_t bytes_collected;
+#endif
+  int * q, ilit;
+  Cls **p, *c;
+  Var * v;
+
+#ifndef NDEDBUG
+  (void) forced;
+#endif
+
+  assert (!ps->mtcls);
+  assert (!satisfied (ps));
+  assert (forced || ps->lsimplify <= ps->propagations);
+  assert (forced || ps->fsimplify <= ps->fixed);
+
+  if (ps->LEVEL)
+    undo (ps, 0);
+#ifndef NFL
+  ps->simplifying = 1;
+  faillits (ps);
+  ps->simplifying = 0;
+
+  if (ps->mtcls)
+    return;
+#endif
+
+  if (ps->cils != ps->cilshead)
+    {
+      assert (ps->ttail == ps->thead);
+      assert (ps->ttail2 == ps->thead);
+      ps->ttail = ps->trail;
+      for (t = ps->trail; t < ps->thead; t++)
+	{
+	  lit = *t;
+	  v = LIT2VAR (lit);
+	  if (v->internal)
+	    {
+	      assert (LIT2INT (lit) < 0);
+	      assert (lit->val == TRUE);
+	      unassign (ps, lit);
+	    }
+	  else
+	    *ps->ttail++ = lit;
+	}
+      ps->ttail2 = ps->thead = ps->ttail;
+
+      for (q = ps->cils; q != ps->cilshead; q++)
+	{
+	  ilit = *q;
+	  assert (0 < ilit && ilit <= (int) ps->max_var);
+	  v = ps->vars + ilit;
+	  assert (v->internal);
+	  v->level = 0;
+	  v->reason = 0;
+	  lit = int2lit (ps, -ilit);
+	  assert (lit->val == UNDEF);
+	  lit->val = TRUE;
+	  notlit = NOTLIT (lit);
+	  assert (notlit->val == UNDEF);
+	  notlit->val = FALSE;
+	}
+    }
+
+  collect = 0;
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+      if (!c)
+	continue;
+
+#ifdef TRACE
+      if (c->collected)
+	continue;
+#endif
+
+      if (c->locked)
+	continue;
+      
+      assert (!c->collect);
+      if (clause_is_toplevel_satisfied (ps, c))
+	{
+	  mark_clause_to_be_collected (c);
+	  collect++;
+	}
+    }
+
+  LOG ( fprintf (ps->out, "%scollecting %d clauses\n", ps->prefix, collect));
+#ifdef STATS
+  bytes_collected = 
+#endif
+  collect_clauses (ps);
+#ifdef STATS
+  ps->srecycled += bytes_collected;
+#endif
+
+  if (ps->cils != ps->cilshead)
+    {
+      for (q = ps->cils; q != ps->cilshead; q++)
+	{
+	  ilit = *q;
+	  assert (0 < ilit && ilit <= (int) ps->max_var);
+	  assert (ps->vars[ilit].internal);
+	  if (ps->rilshead == ps->eorils)
+	    ENLARGE (ps->rils, ps->rilshead, ps->eorils);
+	  *ps->rilshead++ = ilit;
+	  lit = int2lit (ps, -ilit);
+	  assert (lit->val == TRUE);
+	  lit->val = UNDEF;
+	  notlit = NOTLIT (lit);
+	  assert (notlit->val == FALSE);
+	  notlit->val = UNDEF;
+	}
+      ps->cilshead = ps->cils;
+    }
+
+  delta = 10 * (ps->olits + ps->llits) + 100000;
+  if (delta > 2000000)
+    delta = 2000000;
+  ps->lsimplify = ps->propagations + delta;
+  ps->fsimplify = ps->fixed;
+  ps->simps++;
+
+  report (ps, 1, 's');
+}
+
+static void
+iteration (PS * ps)
+{
+  assert (!ps->LEVEL);
+  assert (bcp_queue_is_empty (ps));
+  assert (ps->isimplify < ps->fixed);
+
+  ps->iterations++;
+  report (ps, 2, 'i');
+#ifdef NLUBY
+  ps->drestart = MINRESTART;
+  ps->lrestart = ps->conflicts + ps->drestart;
+#else
+  init_restart (ps);
+#endif
+  ps->isimplify = ps->fixed;
+}
+
+static int
+cmp_glue_activity_size (PS * ps, Cls * c, Cls * d)
+{
+  Act a, b, * p, * q;
+
+  (void) ps;
+
+  assert (c->learned);
+  assert (d->learned);
+
+  if (c->glue < d->glue)		// smaller glue preferred
+    return 1;
+
+  if (c->glue > d->glue)
+    return -1;
+
+  p = CLS2ACT (c);
+  q = CLS2ACT (d);
+  a = *p;
+  b = *q;
+
+  if (a < b)				// then higher activity
+    return -1;
+
+  if (b < a)
+    return 1;
+
+  if (c->size < d->size)		// then smaller size
+    return 1;
+
+  if (c->size > d->size)
+    return -1;
+
+  return 0;
+}
+
+static void
+reduce (PS * ps, unsigned percentage)
+{
+  unsigned redcount, lcollect, collect, target;
+#ifdef STATS
+  size_t bytes_collected;
+#endif
+  Cls **p, *c;
+
+  assert (ps->rhead == ps->resolved);
+
+  ps->lastreduceconflicts = ps->conflicts;
+
+  assert (percentage <= 100);
+  LOG ( fprintf (ps->out, 
+                "%sreducing %u%% learned clauses\n",
+		ps->prefix, percentage));
+
+  while (ps->nlclauses - ps->llocked > (unsigned)(ps->eor - ps->resolved))
+    ENLARGE (ps->resolved, ps->rhead, ps->eor);
+
+  collect = 0;
+  lcollect = 0;
+
+  for (p = ((ps->fsimplify < ps->fixed) ? SOC : ps->lclauses); p != EOC; p = NXC (p))
+    {
+      c = *p;
+      if (!c)
+	continue;
+
+#ifdef TRACE
+      if (c->collected)
+	continue;
+#endif
+
+      if (c->locked)
+	continue;
+
+      assert (!c->collect);
+      if (ps->fsimplify < ps->fixed && clause_is_toplevel_satisfied (ps, c))
+	{
+	  mark_clause_to_be_collected (c);
+	  collect++;
+
+	  if (c->learned && c->size > 2)
+	    lcollect++;
+
+	  continue;
+	}
+
+      if (!c->learned)
+	continue;
+
+      if (c->size <= 2)
+	continue;
+
+      assert (ps->rhead < ps->eor);
+      *ps->rhead++ = c;
+    }
+  assert (ps->rhead <= ps->eor);
+
+  ps->fsimplify = ps->fixed;
+
+  redcount = ps->rhead - ps->resolved;
+  SORT (Cls *, cmp_glue_activity_size, ps->resolved, redcount);
+
+  assert (ps->nlclauses >= lcollect);
+  target = ps->nlclauses - lcollect + 1;
+
+  target = (percentage * target + 99) / 100;
+
+  if (target >= redcount)
+    target = redcount;
+
+  ps->rhead = ps->resolved + target;
+  while (ps->rhead > ps->resolved)
+    {
+      c = *--ps->rhead;
+      mark_clause_to_be_collected (c);
+
+      collect++;
+      if (c->learned && c->size > 2)	/* just for consistency */
+	lcollect++;
+    }
+
+  if (collect)
+    {
+      ps->reductions++;
+#ifdef STATS
+      bytes_collected = 
+#endif
+      collect_clauses (ps);
+#ifdef STATS
+      ps->rrecycled += bytes_collected;
+#endif
+      report (ps, 2, '-');
+    }
+
+  if (!lcollect)
+    inc_lreduce (ps);		/* avoid dead lock */
+
+  assert (ps->rhead == ps->resolved);
+}
+
+static void
+init_reduce (PS * ps)
+{
+  // lreduce = loadded / 2;
+  ps->lreduce = 1000;
+
+  if (ps->lreduce < 100)
+    ps->lreduce = 100;
+
+  if (ps->verbosity)
+     fprintf (ps->out, 
+             "%s\n%sinitial reduction limit %u clauses\n%s\n",
+	     ps->prefix, ps->prefix, ps->lreduce, ps->prefix);
+}
+
+static unsigned
+rng (PS * ps)
+{
+  unsigned res = ps->srng;
+  ps->srng *= 1664525u;
+  ps->srng += 1013904223u;
+  NOLOG ( fprintf (ps->out, "%srng () = %u\n", ps->prefix, res));
+  return res;
+}
+
+static unsigned
+rrng (PS * ps, unsigned low, unsigned high)
+{
+  unsigned long long tmp;
+  unsigned res, elements;
+  assert (low <= high);
+  elements = high - low + 1;
+  tmp = rng (ps);
+  tmp *= elements;
+  tmp >>= 32;
+  tmp += low;
+  res = tmp;
+  NOLOG ( fprintf (ps->out, "%srrng (ps, %u, %u) = %u\n", ps->prefix, low, high, res));
+  assert (low <= res);
+  assert (res <= high);
+  return res;
+}
+
+static Lit *
+decide_phase (PS * ps, Lit * lit)
+{
+  Lit * not_lit = NOTLIT (lit);
+  Var *v = LIT2VAR (lit);
+
+  assert (LIT2SGN (lit) > 0);
+  if (v->usedefphase)
+    {
+      if (v->defphase)
+	{
+	  /* assign to TRUE */
+	}
+      else
+	{
+	  /* assign to FALSE */
+	  lit = not_lit;
+	}
+    }
+  else if (!v->assigned)
+    {
+#ifdef STATS
+      ps->staticphasedecisions++;
+#endif
+      if (ps->defaultphase == POSPHASE)
+	{
+	  /* assign to TRUE */
+	}
+      else if (ps->defaultphase == NEGPHASE)
+	{
+	  /* assign to FALSE */
+	  lit = not_lit;
+	}
+      else if (ps->defaultphase == RNDPHASE)
+	{
+	  /* randomly assign default phase */
+	  if (rrng (ps, 1, 2) != 2)
+	    lit = not_lit;
+	}
+      else if (*LIT2JWH(lit) <= *LIT2JWH (not_lit))
+	{
+	  /* assign to FALSE (Jeroslow-Wang says there are more short
+	   * clauses with negative occurence of this variable, so satisfy
+	   * those, to minimize BCP) 
+	   */
+	  lit = not_lit;
+	}
+      else
+	{
+	  /* assign to TRUE (... but strictly more positive occurrences) */
+	}
+    }
+  else 
+    {
+      /* repeat last phase: phase saving heuristic */
+
+      if (v->phase)
+	{
+	  /* assign to TRUE (last phase was TRUE as well) */
+	}
+      else
+	{
+	  /* assign to FALSE (last phase was FALSE as well) */
+	  lit = not_lit;
+	}
+    }
+
+  return lit;
+}
+
+static unsigned
+gcd (unsigned a, unsigned b)
+{
+  unsigned tmp;
+
+  assert (a);
+  assert (b);
+
+  if (a < b)
+    {
+      tmp = a;
+      a = b;
+      b = tmp;
+    }
+
+  while (b)
+    {
+      assert (a >= b);
+      tmp = b;
+      b = a % b;
+      a = tmp;
+    }
+
+  return a;
+}
+
+static Lit *
+rdecide (PS * ps)
+{
+  unsigned idx, delta, spread;
+  Lit * res;
+
+  spread = RDECIDE;
+  if (rrng (ps, 1, spread) != 2)
+    return 0;
+
+  assert (1 <= ps->max_var);
+  idx = rrng (ps, 1, ps->max_var);
+  res = int2lit (ps, idx);
+
+  if (res->val != UNDEF)
+    {
+      delta = rrng (ps, 1, ps->max_var);
+      while (gcd (delta, ps->max_var) != 1)
+	delta--;
+
+      assert (1 <= delta);
+      assert (delta <= ps->max_var);
+
+      do {
+	idx += delta;
+	if (idx > ps->max_var)
+	  idx -= ps->max_var;
+	res = int2lit (ps, idx);
+      } while (res->val != UNDEF);
+    }
+
+#ifdef STATS
+  ps->rdecisions++;
+#endif
+  res = decide_phase (ps, res);
+  LOG ( fprintf (ps->out, "%srdecide %d\n", ps->prefix, LIT2INT (res)));
+
+  return res;
+}
+
+static Lit *
+sdecide (PS * ps)
+{
+  Lit *res;
+  Rnk *r;
+
+  for (;;)
+    {
+      r = htop (ps);
+      res = RNK2LIT (r);
+      if (res->val == UNDEF) break;
+      (void) hpop (ps);
+      NOLOG ( fprintf (ps->out, 
+                      "%shpop %u %u %u\n",
+		      ps->prefix, r - ps->rnks,
+		      FLTMANTISSA(r->score),
+		      FLTEXPONENT(r->score)));
+    }
+
+#ifdef STATS
+  ps->sdecisions++;
+#endif
+  res = decide_phase (ps, res);
+
+  LOG ( fprintf (ps->out, "%ssdecide %d\n", ps->prefix, LIT2INT (res)));
+
+  return res;
+}
+
+static Lit *
+adecide (PS * ps)
+{
+  Lit *lit;
+  Var * v;
+
+  assert (ps->als < ps->alshead);
+  assert (!ps->failed_assumption);
+
+  while (ps->alstail < ps->alshead)
+    {
+      lit = *ps->alstail++;
+
+      if (lit->val == FALSE)
+	{
+	  ps->failed_assumption = lit;
+	  v = LIT2VAR (lit);
+
+	  use_var (ps, v);
+
+	  LOG ( fprintf (ps->out, "%sfirst failed assumption %d\n",
+			ps->prefix, LIT2INT (ps->failed_assumption)));
+	  fanalyze (ps);
+	  return 0;
+	}
+
+      if (lit->val == TRUE)
+	{
+	  v = LIT2VAR (lit);
+	  if (v->level > ps->adecidelevel)
+	    ps->adecidelevel = v->level;
+	  continue;
+	}
+
+#ifdef STATS
+      ps->assumptions++;
+#endif
+      LOG ( fprintf (ps->out, "%sadecide %d\n", ps->prefix, LIT2INT (lit)));
+      ps->adecidelevel = ps->LEVEL + 1;
+
+      return lit;
+    }
+
+  return 0;
+}
+
+static void
+decide (PS * ps)
+{
+  Lit * lit;
+
+  assert (!satisfied (ps));
+  assert (!ps->conflict);
+
+  if (ps->alstail < ps->alshead && (lit = adecide (ps)))
+    ;
+  else if (ps->failed_assumption)
+    return;
+  else if (satisfied (ps))
+    return;
+  else if (!(lit = rdecide (ps)))
+    lit = sdecide (ps);
+
+  assert (lit);
+  assign_decision (ps, lit);
+
+  ps->levelsum += ps->LEVEL;
+  ps->decisions++;
+}
+
+static int
+sat (PS * ps, int l)
+{
+  int count = 0, backtracked;
+
+  if (!ps->conflict)
+    bcp (ps);
+
+  if (ps->conflict)
+    backtrack (ps);
+
+  if (ps->mtcls)
+    return PICOSAT_UNSATISFIABLE;
+
+  if (satisfied (ps))
+    goto SATISFIED;
+
+  if (ps->lsimplify <= ps->propagations)
+    simplify (ps, 0);
+
+  if (ps->mtcls)
+    return PICOSAT_UNSATISFIABLE;
+
+  if (satisfied (ps))
+    goto SATISFIED;
+
+  init_restart (ps);
+
+  if (!ps->lreduce)
+    init_reduce (ps);
+
+  ps->isimplify = ps->fixed;
+  backtracked = 0;
+
+  for (;;)
+    {
+      if (!ps->conflict)
+	bcp (ps);
+
+      if (ps->conflict)
+	{
+	  incincs (ps);
+	  backtrack (ps);
+
+	  if (ps->mtcls)
+	    return PICOSAT_UNSATISFIABLE;
+	  backtracked = 1;
+	  continue;
+	}
+
+      if (satisfied (ps))
+	{
+SATISFIED:
+#ifndef NDEBUG
+	  original_clauses_satisfied (ps);
+	  assumptions_satisfied (ps);
+#endif
+	  return PICOSAT_SATISFIABLE;
+	}
+
+      if (backtracked)
+	{
+	  backtracked = 0;
+	  if (!ps->LEVEL && ps->isimplify < ps->fixed)
+	    iteration (ps);
+	}
+
+      if (l >= 0 && count >= l)		/* decision limit reached ? */
+	return PICOSAT_UNKNOWN;
+
+      if (ps->interrupt.function &&		/* external interrupt */
+	  count > 0 && !(count % INTERRUPTLIM) &&
+	  ps->interrupt.function (ps->interrupt.state))
+	return PICOSAT_UNKNOWN;
+
+      if (ps->propagations >= ps->lpropagations)/* propagation limit reached ? */
+	return PICOSAT_UNKNOWN;
+
+#ifndef NADC
+      if (!ps->adodisabled && ps->adoconflicts >= ps->adoconflictlimit)
+	{
+	  assert (bcp_queue_is_empty (ps));
+	  return PICOSAT_UNKNOWN;
+	}
+#endif
+
+      if (ps->fsimplify < ps->fixed && ps->lsimplify <= ps->propagations)
+	{
+	  simplify (ps, 0);
+	  if (!bcp_queue_is_empty (ps))
+	    continue;
+#ifndef NFL
+	  if (ps->mtcls)
+	    return PICOSAT_UNSATISFIABLE;
+
+	  if (satisfied (ps))
+	    return PICOSAT_SATISFIABLE;
+
+	  assert (!ps->LEVEL);
+#endif
+	}
+
+      if (need_to_reduce (ps))
+	reduce (ps, 50);
+
+      if (ps->conflicts >= ps->lrestart && ps->LEVEL > 2)
+	restart (ps);
+
+      decide (ps);
+      if (ps->failed_assumption)
+	return PICOSAT_UNSATISFIABLE;
+      count++;
+    }
+}
+
+static void
+rebias (PS * ps)
+{
+  Cls ** p, * c;
+  Var * v;
+
+  for (v = ps->vars + 1; v <= ps->vars + ps->max_var; v++)
+    v->assigned = 0;
+
+  memset (ps->jwh, 0, 2 * (ps->max_var + 1) * sizeof *ps->jwh);
+
+  for (p = ps->oclauses; p < ps->ohead; p++) 
+    {
+      c = *p;
+
+      if (!c) 
+	continue;
+
+      if (c->learned)
+	continue;
+
+      incjwh (ps, c);
+    }
+}
+
+#ifdef TRACE
+
+static unsigned
+core (PS * ps)
+{
+  unsigned idx, prev, this, delta, i, lcore, vcore;
+  unsigned *stack, *shead, *eos;
+  Lit **q, **eol, *lit;
+  Cls *c, *reason;
+  Znt *p, byte;
+  Zhn *zhain;
+  Var *v;
+
+  assert (ps->trace);
+
+  assert (ps->mtcls || ps->failed_assumption);
+  if (ps->ocore >= 0)
+    return ps->ocore;
+
+  lcore = ps->ocore = vcore = 0;
+
+  stack = shead = eos = 0;
+  ENLARGE (stack, shead, eos);
+
+  if (ps->mtcls)
+    {
+      idx = CLS2IDX (ps->mtcls);
+      *shead++ = idx;
+    }
+  else
+    {
+      assert (ps->failed_assumption);
+      v = LIT2VAR (ps->failed_assumption);
+      reason = v->reason;
+      assert (reason);
+      idx = CLS2IDX (reason);
+      *shead++ = idx;
+    }
+
+  while (shead > stack)
+    {
+      idx = *--shead;
+      zhain = IDX2ZHN (idx);
+
+      if (zhain)
+	{
+	  if (zhain->core)
+	    continue;
+
+	  zhain->core = 1;
+	  lcore++;
+
+	  c = IDX2CLS (idx);
+	  if (c)
+	    {
+	      assert (!c->core);
+	      c->core = 1;
+	    }
+
+	  i = 0;
+	  delta = 0;
+	  prev = 0;
+	  for (p = zhain->znt; (byte = *p); p++, i += 7)
+	    {
+	      delta |= (byte & 0x7f) << i;
+	      if (byte & 0x80)
+		continue;
+
+	      this = prev + delta;
+	      assert (prev < this);	/* no overflow */
+
+	      if (shead == eos)
+		ENLARGE (stack, shead, eos);
+	      *shead++ = this;
+
+	      prev = this;
+	      delta = 0;
+	      i = -7;
+	    }
+	}
+      else
+	{
+	  c = IDX2CLS (idx);
+
+	  assert (c);
+	  assert (!c->learned);
+
+	  if (c->core)
+	    continue;
+
+	  c->core = 1;
+	  ps->ocore++;
+
+	  eol = end_of_lits (c);
+	  for (q = c->lits; q < eol; q++)
+	    {
+	      lit = *q;
+	      v = LIT2VAR (lit);
+	      if (v->core)
+		continue;
+
+	      v->core = 1;
+	      vcore++;
+
+	      if (!ps->failed_assumption) continue;
+	      if (lit != ps->failed_assumption) continue;
+
+	      reason = v->reason;
+	      if (!reason) continue;
+	      if (reason->core) continue;
+
+	      idx = CLS2IDX (reason);
+	      if (shead == eos)
+		ENLARGE (stack, shead, eos);
+	      *shead++ = idx;
+	    }
+	}
+    }
+
+  DELETEN (stack, eos - stack);
+
+  if (ps->verbosity)
+     fprintf (ps->out,
+	     "%s%u core variables out of %u (%.1f%%)\n"
+	     "%s%u core original clauses out of %u (%.1f%%)\n"
+	     "%s%u core learned clauses out of %u (%.1f%%)\n",
+	     ps->prefix, vcore, ps->max_var, PERCENT (vcore, ps->max_var),
+	     ps->prefix, ps->ocore, ps->oadded, PERCENT (ps->ocore, ps->oadded),
+	     ps->prefix, lcore, ps->ladded, PERCENT (lcore, ps->ladded));
+
+  return ps->ocore;
+}
+
+static void
+trace_lits (PS * ps, Cls * c, FILE * file)
+{
+  Lit **p, **eol = end_of_lits (c);
+
+  assert (c);
+  assert (c->core);
+
+  for (p = c->lits; p < eol; p++)
+    fprintf (file, "%d ", LIT2INT (*p));
+
+  fputc ('0', file);
+}
+
+static void
+write_idx (PS * ps, unsigned idx, FILE * file)
+{
+  fprintf (file, "%ld", EXPORTIDX (idx));
+}
+
+static void
+trace_clause (PS * ps, unsigned idx, Cls * c, FILE * file, int fmt)
+{
+  assert (c);
+  assert (c->core);
+  assert (fmt == RUP_TRACE_FMT || !c->learned);
+  assert (CLS2IDX (c) == idx);
+
+  if (fmt != RUP_TRACE_FMT)
+    {
+      write_idx (ps, idx, file);
+      fputc (' ', file);
+    }
+
+  trace_lits (ps, c, file);
+
+  if (fmt != RUP_TRACE_FMT)
+    fputs (" 0", file);
+
+  fputc ('\n', file);
+}
+
+static void
+trace_zhain (PS * ps, unsigned idx, Zhn * zhain, FILE * file, int fmt)
+{
+  unsigned prev, this, delta, i;
+  Znt *p, byte;
+  Cls * c;
+
+  assert (zhain);
+  assert (zhain->core);
+
+  write_idx (ps, idx, file);
+  fputc (' ', file);
+
+  if (fmt == EXTENDED_TRACECHECK_TRACE_FMT)
+    {
+      c = IDX2CLS (idx);
+      assert (c);
+      trace_lits (ps, c, file);
+    }
+  else
+    {
+      assert (fmt == COMPACT_TRACECHECK_TRACE_FMT);
+      putc ('*', file);
+    }
+
+  i = 0;
+  delta = 0;
+  prev = 0;
+
+  for (p = zhain->znt; (byte = *p); p++, i += 7)
+    {
+      delta |= (byte & 0x7f) << i;
+      if (byte & 0x80)
+	continue;
+
+      this = prev + delta;
+
+      putc (' ', file);
+      write_idx (ps, this, file);
+
+      prev = this;
+      delta = 0;
+      i = -7;
+    }
+
+  fputs (" 0\n", file);
+}
+
+static void
+write_core (PS * ps, FILE * file)
+{
+  Lit **q, **eol;
+  Cls **p, *c;
+
+  fprintf (file, "p cnf %u %u\n", ps->max_var, core (ps));
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+
+      if (!c || c->learned || !c->core)
+	continue;
+
+      eol = end_of_lits (c);
+      for (q = c->lits; q < eol; q++)
+	fprintf (file, "%d ", LIT2INT (*q));
+
+      fputs ("0\n", file);
+    }
+}
+
+#endif
+
+static void
+write_trace (PS * ps, FILE * file, int fmt)
+{
+#ifdef TRACE
+  Cls *c, ** p;
+  Zhn *zhain;
+  unsigned i;
+
+  core (ps);
+
+  if (fmt == RUP_TRACE_FMT)
+    {
+      ps->rupvariables = picosat_variables (ps),
+      ps->rupclauses = picosat_added_original_clauses (ps);
+      write_rup_header (ps, file);
+    }
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+
+      if (ps->oclauses <= p && p < ps->eoo)
+	{
+	  i = OIDX2IDX (p - ps->oclauses);
+	  assert (!c || CLS2IDX (c) == i);
+	}
+      else
+	{
+          assert (ps->lclauses <= p && p < ps->EOL);
+	  i = LIDX2IDX (p - ps->lclauses);
+	}
+
+      zhain = IDX2ZHN (i);
+
+      if (zhain)
+	{
+	  if (zhain->core)
+	    {
+	      if (fmt == RUP_TRACE_FMT)
+		trace_clause (ps,i, c, file, fmt);
+	      else
+		trace_zhain (ps, i, zhain, file, fmt);
+	    }
+	}
+      else if (c)
+	{
+	  if (fmt != RUP_TRACE_FMT && c)
+	    {
+	      if (c->core)
+		trace_clause (ps, i, c, file, fmt);
+	    }
+	}
+    }
+#else
+  (void) file;
+  (void) fmt;
+  (void) ps;
+#endif
+}
+
+static void
+write_core_wrapper (PS * ps, FILE * file, int fmt)
+{
+  (void) fmt;
+#ifdef TRACE
+  write_core (ps, file);
+#else
+  (void) ps;
+  (void) file;
+#endif
+}
+
+static Lit *
+import_lit (PS * ps, int lit, int nointernal)
+{
+  Lit * res;
+  Var * v;
+
+  ABORTIF (lit == INT_MIN, "API usage: INT_MIN literal");
+  ABORTIF (abs (lit) > (int) ps->max_var && ps->CLS != ps->clshead,
+           "API usage: new variable index after 'picosat_push'");
+
+  if (abs (lit) <= (int) ps->max_var)
+    {
+      res = int2lit (ps, lit);
+      v = LIT2VAR (res);
+      if (nointernal && v->internal)
+	ABORT ("API usage: trying to import invalid literal");
+      else if (!nointernal && !v->internal)
+	ABORT ("API usage: trying to import invalid context");
+    }
+  else
+    {
+      while (abs (lit) > (int) ps->max_var)
+	inc_max_var (ps);
+      res = int2lit (ps, lit);
+    }
+
+  return res;
+}
+
+#ifdef TRACE
+static void
+reset_core (PS * ps)
+{
+  Cls ** p, * c;
+  Zhn ** q, * z;
+  unsigned i;
+
+  for (i = 1; i <= ps->max_var; i++)
+    ps->vars[i].core = 0;
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    if ((c = *p))
+      c->core = 0;
+
+  for (q = ps->zhains; q != ps->zhead; q++)
+    if ((z = *q))
+      z->core = 0;
+
+  ps->ocore = -1;
+}
+#endif
+
+static void
+reset_assumptions (PS * ps)
+{
+  Lit ** p;
+
+  ps->failed_assumption = 0;
+
+  if (ps->extracted_all_failed_assumptions)
+    {
+      for (p = ps->als; p < ps->alshead; p++)
+	LIT2VAR (*p)->failed = 0;
+
+      ps->extracted_all_failed_assumptions = 0;
+    }
+
+  ps->alstail = ps->alshead = ps->als;
+  ps->adecidelevel = 0;
+}
+
+static void
+check_ready (PS * ps)
+{
+  ABORTIF (!ps || ps->state == RESET, "API usage: uninitialized");
+}
+
+static void
+check_sat_state (PS * ps)
+{
+  ABORTIF (ps->state != SAT, "API usage: expected to be in SAT state");
+}
+
+static void
+check_unsat_state (PS * ps)
+{
+  ABORTIF (ps->state != UNSAT, "API usage: expected to be in UNSAT state");
+}
+
+static void
+check_sat_or_unsat_or_unknown_state (PS * ps)
+{
+  ABORTIF (ps->state != SAT && ps->state != UNSAT && ps->state != UNKNOWN,
+           "API usage: expected to be in SAT, UNSAT, or UNKNOWN state");
+}
+
+static void
+reset_partial (PS * ps)
+{
+  unsigned idx;
+  if (!ps->partial)
+    return;
+  for (idx = 1; idx <= ps->max_var; idx++)
+    ps->vars[idx].partial = 0;
+  ps->partial = 0;
+}
+
+static void
+reset_incremental_usage (PS * ps)
+{
+  unsigned num_non_false;
+  Lit * lit, ** q;
+
+  check_sat_or_unsat_or_unknown_state (ps);
+
+  LOG ( fprintf (ps->out, "%sRESET incremental usage\n", ps->prefix));
+
+  if (ps->LEVEL)
+    undo (ps, 0);
+
+  reset_assumptions (ps);
+
+  if (ps->conflict)
+    { 
+      num_non_false = 0;
+      for (q = ps->conflict->lits; q < end_of_lits (ps->conflict); q++)
+	{
+	  lit = *q;
+	  if (lit->val != FALSE)
+	    num_non_false++;
+	}
+
+      // assert (num_non_false >= 2); // TODO: why this assertion?
+#ifdef NO_BINARY_CLAUSES
+      if (ps->conflict == &ps->cimpl)
+	resetcimpl (ps);
+#endif
+#ifndef NADC
+      if (ps->conflict == ps->adoconflict)
+	resetadoconflict (ps);
+#endif
+      ps->conflict = 0;
+    }
+
+#ifdef TRACE
+  reset_core (ps);
+#endif
+
+  reset_partial (ps);
+
+  ps->saved_flips = ps->flips;
+  ps->min_flipped = UINT_MAX;
+  ps->saved_max_var = ps->max_var;
+
+  ps->state = READY;
+}
+
+static void
+enter (PS * ps)
+{
+  if (ps->nentered++)
+    return;
+
+  check_ready (ps);
+  ps->entered = picosat_time_stamp ();
+}
+
+static void
+leave (PS * ps)
+{
+  assert (ps->nentered);
+  if (--ps->nentered)
+    return;
+
+  sflush (ps);
+}
+
+static void
+check_trace_support_and_execute (PS * ps,
+                                 FILE * file, 
+				 void (*f)(PS*,FILE*,int), int fmt)
+{
+  check_ready (ps);
+  check_unsat_state (ps);
+#ifdef TRACE
+  ABORTIF (!ps->trace, "API usage: tracing disabled");
+  enter (ps);
+  f (ps, file, fmt);
+  leave (ps);
+#else
+  (void) file;
+  (void) fmt;
+  (void) f;
+  ABORT ("compiled without trace support");
+#endif
+}
+
+static void
+extract_all_failed_assumptions (PS * ps)
+{
+  Lit ** p, ** eol;
+  Var * v, * u;
+  int pos;
+  Cls * c;
+
+  assert (!ps->extracted_all_failed_assumptions);
+
+  assert (ps->failed_assumption);
+  assert (ps->mhead == ps->marked);
+
+  if (ps->marked == ps->eom)
+    ENLARGE (ps->marked, ps->mhead, ps->eom);
+
+  v = LIT2VAR (ps->failed_assumption);
+  mark_var (ps, v);
+  pos = 0;
+
+  while (pos < ps->mhead - ps->marked)
+    {
+      v = ps->marked[pos++];
+      assert (v->mark);
+      c = var2reason (ps, v);
+      if (!c)
+	continue;
+      eol = end_of_lits (c);
+      for (p = c->lits; p < eol; p++)
+	{
+	  u = LIT2VAR (*p);
+	  if (!u->mark)
+	    mark_var (ps, u);
+	}
+#ifdef NO_BINARY_CLAUSES
+      if (c == &ps->impl)
+	resetimpl (ps);
+#endif
+    }
+
+  for (p = ps->als; p < ps->alshead; p++)
+    {
+      u = LIT2VAR (*p);
+      if (!u->mark) continue;
+      u->failed = 1;
+      LOG ( fprintf (ps->out,
+                     "%sfailed assumption %d\n",
+		     ps->prefix, LIT2INT (*p)));
+    }
+
+  while (ps->mhead > ps->marked)
+    (*--ps->mhead)->mark = 0;
+
+  ps->extracted_all_failed_assumptions = 1;
+}
+
+const char *
+picosat_copyright (void)
+{
+  return "Copyright (c) 2006 - 2014 Armin Biere JKU Linz";
+}
+
+PicoSAT *
+picosat_init (void)
+{
+  return init (0, 0, 0, 0);
+}
+
+PicoSAT * 
+picosat_minit (void * pmgr,
+	       picosat_malloc pnew,
+	       picosat_realloc presize,
+	       picosat_free pfree)
+{
+  ABORTIF (!pnew, "API usage: zero 'picosat_malloc' argument");
+  ABORTIF (!presize, "API usage: zero 'picosat_realloc' argument");
+  ABORTIF (!pfree, "API usage: zero 'picosat_free' argument");
+  return init (pmgr, pnew, presize, pfree);
+}
+
+
+void
+picosat_adjust (PS * ps, int new_max_var)
+{
+  unsigned new_size_vars;
+
+  ABORTIF (abs (new_max_var) > (int) ps->max_var && ps->CLS != ps->clshead,
+           "API usage: adjusting variable index after 'picosat_push'");
+  enter (ps);
+
+  new_max_var = abs (new_max_var);
+  new_size_vars = new_max_var + 1;
+
+  if (ps->size_vars < new_size_vars)
+    enlarge (ps, new_size_vars);
+
+  while (ps->max_var < (unsigned) new_max_var)
+    inc_max_var (ps);
+
+  leave (ps);
+}
+
+int
+picosat_inc_max_var (PS * ps)
+{
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  inc_max_var (ps);
+
+  if (ps->measurealltimeinlib)
+    leave (ps);
+
+  return ps->max_var;
+}
+
+int
+picosat_context (PS * ps)
+{
+  return ps->clshead == ps->CLS ? 0 : LIT2INT (ps->clshead[-1]);
+}
+
+int
+picosat_push (PS * ps)
+{
+  int res;
+  Lit *lit;
+  Var * v;
+
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  if (ps->state != READY)
+    reset_incremental_usage (ps);
+
+  if (ps->rils != ps->rilshead)
+    {
+      res = *--ps->rilshead;
+      assert (ps->vars[res].internal);
+    }
+  else
+    {
+      inc_max_var (ps);
+      res = ps->max_var;
+      v = ps->vars + res;
+      assert (!v->internal);
+      v->internal = 1;
+      ps->internals++;
+      LOG ( fprintf (ps->out, "%snew internal variable index %d\n", ps->prefix, res));
+    }
+
+  lit = int2lit (ps, res);
+
+  if (ps->clshead == ps->eocls)
+    ENLARGE (ps->CLS, ps->clshead, ps->eocls);
+  *ps->clshead++ = lit;
+
+  ps->contexts++;
+
+  LOG ( fprintf (ps->out, "%snew context %d at depth %ld after push\n",
+                 ps->prefix, res, (long)(ps->clshead - ps->CLS)));
+
+  if (ps->measurealltimeinlib)
+    leave (ps);
+
+  return res;
+}
+
+int 
+picosat_pop (PS * ps)
+{
+  Lit * lit;
+  int res;
+  ABORTIF (ps->CLS == ps->clshead, "API usage: too many 'picosat_pop'");
+  ABORTIF (ps->added != ps->ahead, "API usage: incomplete clause");
+
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  if (ps->state != READY)
+    reset_incremental_usage (ps);
+
+  assert (ps->CLS < ps->clshead);
+  lit = *--ps->clshead;
+  LOG ( fprintf (ps->out, "%sclosing context %d at depth %ld after pop\n",
+                 ps->prefix, LIT2INT (lit), (long)(ps->clshead - ps->CLS) + 1));
+
+  if (ps->cilshead == ps->eocils)
+    ENLARGE (ps->cils, ps->cilshead, ps->eocils);
+  *ps->cilshead++ = LIT2INT (lit);
+
+  if (ps->cilshead - ps->cils > MAXCILS) {
+    LOG ( fprintf (ps->out,
+                  "%srecycling %ld interals with forced simplification\n",
+		  ps->prefix, (long)(ps->cilshead - ps->cils)));
+    simplify (ps, 1);
+  }
+
+  res = picosat_context (ps);
+  if (res)
+    LOG ( fprintf (ps->out, "%snew context %d at depth %ld after pop\n",
+		   ps->prefix, res, (long)(ps->clshead - ps->CLS)));
+  else
+    LOG ( fprintf (ps->out, "%souter most context reached after pop\n", ps->prefix));
+
+  if (ps->measurealltimeinlib)
+    leave (ps);
+  
+  return res;
+}
+
+void
+picosat_set_verbosity (PS * ps, int new_verbosity_level)
+{
+  check_ready (ps);
+  ps->verbosity = new_verbosity_level;
+}
+
+void
+picosat_set_plain (PS * ps, int new_plain_value)
+{
+  check_ready (ps);
+  ps->plain = new_plain_value;
+}
+
+int
+picosat_enable_trace_generation (PS * ps)
+{
+  int res = 0;
+  check_ready (ps);
+#ifdef TRACE
+  ABORTIF (ps->addedclauses, 
+           "API usage: trace generation enabled after adding clauses");
+  res = ps->trace = 1;
+#endif
+  return res;
+}
+
+void
+picosat_set_incremental_rup_file (PS * ps, FILE * rup_file, int m, int n)
+{
+  check_ready (ps);
+  assert (!ps->rupstarted);
+  ps->rup = rup_file;
+  ps->rupvariables = m;
+  ps->rupclauses = n;
+}
+
+void
+picosat_set_output (PS * ps, FILE * output_file)
+{
+  check_ready (ps);
+  ps->out = output_file;
+}
+
+void
+picosat_measure_all_calls (PS * ps)
+{
+  check_ready (ps);
+  ps->measurealltimeinlib = 1;
+}
+
+void
+picosat_set_prefix (PS * ps, const char * str)
+{
+  check_ready (ps);
+  new_prefix (ps, str);
+}
+
+void
+picosat_set_seed (PS * ps, unsigned s)
+{
+  check_ready (ps);
+  ps->srng = s;
+}
+
+void
+picosat_reset (PS * ps)
+{
+  check_ready (ps);
+  reset (ps);
+}
+
+int
+picosat_add (PS * ps, int int_lit)
+{
+  int res = ps->oadded;
+  Lit *lit;
+
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  ABORTIF (ps->rup && ps->rupstarted && ps->oadded >= (unsigned)ps->rupclauses,
+           "API usage: adding too many clauses after RUP header written");
+#ifndef NADC
+  ABORTIF (ps->addingtoado, 
+           "API usage: 'picosat_add' and 'picosat_add_ado_lit' mixed");
+#endif
+  if (ps->state != READY)
+    reset_incremental_usage (ps);
+
+  if (ps->saveorig)
+    {
+      if (ps->sohead == ps->eoso)
+	ENLARGE (ps->soclauses, ps->sohead, ps->eoso);
+
+      *ps->sohead++ = int_lit;
+    }
+
+  if (int_lit)
+    {
+      lit = import_lit (ps, int_lit, 1);
+      add_lit (ps, lit);
+    }
+  else
+    simplify_and_add_original_clause (ps);
+
+  if (ps->measurealltimeinlib)
+    leave (ps);
+
+  return res;
+}
+
+int
+picosat_add_arg (PS * ps, ...)
+{
+  int lit;
+  va_list ap;
+  va_start (ap, ps);
+  while ((lit = va_arg (ap, int)))
+    (void) picosat_add (ps, lit);
+  va_end (ap);
+  return picosat_add (ps, 0);
+}
+
+int
+picosat_add_lits (PS * ps, int * lits)
+{
+  const int * p;
+  int lit;
+  for (p = lits; (lit = *p); p++)
+    (void) picosat_add (ps, lit);
+  return picosat_add (ps, 0);
+}
+
+void
+picosat_add_ado_lit (PS * ps, int external_lit)
+{
+#ifndef NADC
+  Lit * internal_lit;
+
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  if (ps->state != READY)
+    reset_incremental_usage (ps);
+
+  ABORTIF (!ps->addingtoado && ps->ahead > ps->added,
+           "API usage: 'picosat_add' and 'picosat_add_ado_lit' mixed");
+
+  if (external_lit)
+    {
+      ps->addingtoado = 1;
+      internal_lit = import_lit (ps, external_lit, 1);
+      add_lit (ps, internal_lit);
+    }
+  else
+    {
+      ps->addingtoado = 0;
+      add_ado (ps);
+    }
+  if (ps->measurealltimeinlib)
+    leave (ps);
+#else
+  (void) ps;
+  (void) external_lit;
+  ABORT ("compiled without all different constraint support");
+#endif
+}
+
+static void
+assume (PS * ps, Lit * lit)
+{
+  if (ps->alshead == ps->eoals)
+    {
+      assert (ps->alstail == ps->als);
+      ENLARGE (ps->als, ps->alshead, ps->eoals);
+      ps->alstail = ps->als;
+    }
+
+  *ps->alshead++ = lit;
+  LOG ( fprintf (ps->out, "%sassumption %d\n", ps->prefix, LIT2INT (lit)));
+}
+
+static void
+assume_contexts (PS * ps)
+{
+  Lit ** p;
+  if (ps->als != ps->alshead)
+    return;
+  for (p = ps->CLS; p != ps->clshead; p++)
+    assume (ps, *p);
+}
+
+#ifndef RCODE
+static const char * enumstr (int i) {
+  int last = i % 10;
+  if (last == 1) return "st";
+  if (last == 2) return "nd";
+  if (last == 3) return "rd";
+  return "th";
+}
+#endif
+
+static int
+tderef (PS * ps, int int_lit)
+{
+  Lit * lit;
+  Var * v;
+
+  assert (abs (int_lit) <= (int) ps->max_var);
+
+  lit = int2lit (ps, int_lit);
+
+  v = LIT2VAR (lit);
+  if (v->level > 0)
+    return 0;
+
+  if (lit->val == TRUE)
+    return 1;
+
+  if (lit->val == FALSE)
+    return -1;
+
+  return 0;
+}
+
+static int
+pderef (PS * ps, int int_lit)
+{
+  Lit * lit;
+  Var * v;
+
+  assert (abs (int_lit) <= (int) ps->max_var);
+
+  v = ps->vars + abs (int_lit);
+  if (!v->partial)
+    return 0;
+
+  lit = int2lit (ps, int_lit);
+
+  if (lit->val == TRUE)
+    return 1;
+
+  if (lit->val == FALSE)
+    return -1;
+
+  return 0;
+}
+
+static void
+minautarky (PS * ps)
+{
+  unsigned * occs, maxoccs, tmpoccs, npartial;
+  int * p, * c, lit, best, val;
+#ifdef LOGGING
+  int tl;
+#endif
+
+  assert (!ps->partial);
+
+  npartial = 0;
+
+  NEWN (occs, 2*ps->max_var + 1);
+  CLRN (occs, 2*ps->max_var + 1);
+  occs += ps->max_var;
+  for (p = ps->soclauses; p < ps->sohead; p++)
+    occs[*p]++;
+  assert (occs[0] == ps->oadded);
+
+  for (c = ps->soclauses; c < ps->sohead; c = p + 1) 
+    {
+#ifdef LOGGING
+      tl = 0;
+#endif
+      best = 0; 
+      maxoccs = 0;
+      for (p = c; (lit = *p); p++)
+	{
+	  val = tderef (ps, lit);
+	  if (val < 0)
+	    continue;
+	  if (val > 0)
+	    {
+#ifdef LOGGING
+	      tl = 1;
+#endif
+	      best = lit;
+	      maxoccs = occs[lit];
+	    }
+
+	  val = pderef (ps, lit);
+	  if (val > 0)
+	    break;
+	  if (val < 0)
+	    continue;
+	  val = int2lit (ps, lit)->val;
+	  assert (val);
+	  if (val < 0)
+	    continue;
+	  tmpoccs = occs[lit];
+	  if (best && tmpoccs <= maxoccs)
+	    continue;
+	  best = lit;
+	  maxoccs = tmpoccs;
+	}
+      if (!lit)
+	{
+	  assert (best);
+	  LOG ( fprintf (ps->out, "%sautark %d with %d occs%s\n", 
+	       ps->prefix, best, maxoccs, tl ? " (top)" : ""));
+	  ps->vars[abs (best)].partial = 1;
+	  npartial++;
+	}
+      for (p = c; (lit = *p); p++)
+	{
+	  assert (occs[lit] > 0);
+	  occs[lit]--;
+	}
+    }
+  occs -= ps->max_var;
+  DELETEN (occs, 2*ps->max_var + 1);
+  ps->partial = 1;
+
+  if (ps->verbosity)
+     fprintf (ps->out,
+      "%sautarky of size %u out of %u satisfying all clauses (%.1f%%)\n",
+      ps->prefix, npartial, ps->max_var, PERCENT (npartial, ps->max_var));
+}
+
+void
+picosat_assume (PS * ps, int int_lit)
+{
+  Lit *lit;
+
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  if (ps->state != READY)
+    reset_incremental_usage (ps);
+
+  assume_contexts (ps);
+  lit = import_lit (ps, int_lit, 1);
+  assume (ps, lit);
+
+  if (ps->measurealltimeinlib)
+    leave (ps);
+}
+
+int
+picosat_sat (PS * ps, int l)
+{
+  int res;
+  char ch;
+
+  enter (ps);
+
+  ps->calls++;
+  LOG ( fprintf (ps->out, "%sSTART call %u\n", ps->prefix, ps->calls));
+
+  if (ps->added < ps->ahead)
+    {
+#ifndef NADC
+      if (ps->addingtoado)
+	ABORT ("API usage: incomplete all different constraint");
+      else
+#endif
+	ABORT ("API usage: incomplete clause");
+    }
+
+  if (ps->state != READY)
+    reset_incremental_usage (ps);
+
+  assume_contexts (ps);
+
+  res = sat (ps, l);
+
+  assert (ps->state == READY);
+
+  switch (res)
+    {
+    case PICOSAT_UNSATISFIABLE:
+      ch = '0';
+      ps->state = UNSAT;
+      break;
+    case PICOSAT_SATISFIABLE:
+      ch = '1';
+      ps->state = SAT;
+      break;
+    default:
+      ch = '?';
+      ps->state = UNKNOWN;
+      break;
+    }
+
+  if (ps->verbosity)
+    {
+      report (ps, 1, ch);
+      rheader (ps);
+    }
+
+  leave (ps);
+  LOG ( fprintf (ps->out, "%sEND call %u result %d\n", ps->prefix, ps->calls, res));
+
+  ps->last_sat_call_result = res;
+
+  return res;
+}
+
+int
+picosat_res (PS * ps)
+{
+  return ps->last_sat_call_result;
+}
+
+int
+picosat_deref (PS * ps, int int_lit)
+{
+  Lit *lit;
+
+  check_ready (ps);
+  check_sat_state (ps);
+  ABORTIF (!int_lit, "API usage: can not deref zero literal");
+  ABORTIF (ps->mtcls, "API usage: deref after empty clause generated");
+
+#ifdef STATS
+  ps->derefs++;
+#endif
+
+  if (abs (int_lit) > (int) ps->max_var)
+    return 0;
+
+  lit = int2lit (ps, int_lit);
+
+  if (lit->val == TRUE)
+    return 1;
+
+  if (lit->val == FALSE)
+    return -1;
+
+  return 0;
+}
+
+int
+picosat_deref_toplevel (PS * ps, int int_lit)
+{
+  check_ready (ps);
+  ABORTIF (!int_lit, "API usage: can not deref zero literal");
+
+#ifdef STATS
+  ps->derefs++;
+#endif
+  if (abs (int_lit) > (int) ps->max_var)
+    return 0;
+
+  return tderef (ps, int_lit);
+}
+
+int
+picosat_inconsistent (PS * ps)
+{
+  check_ready (ps);
+  return ps->mtcls != 0;
+}
+
+int
+picosat_corelit (PS * ps, int int_lit)
+{
+  check_ready (ps);
+  check_unsat_state (ps);
+  ABORTIF (!int_lit, "API usage: zero literal can not be in core");
+
+  assert (ps->mtcls || ps->failed_assumption);
+
+#ifdef TRACE
+  {
+    int res = 0;
+    ABORTIF (!ps->trace, "tracing disabled");
+    if (ps->measurealltimeinlib)
+      enter (ps);
+    core (ps);
+    if (abs (int_lit) <= (int) ps->max_var)
+      res = ps->vars[abs (int_lit)].core;
+    assert (!res || ps->failed_assumption || ps->vars[abs (int_lit)].used);
+    if (ps->measurealltimeinlib)
+      leave (ps);
+    return res;
+  }
+#else
+  ABORT ("compiled without trace support");
+  return 0;
+#endif
+}
+
+int
+picosat_coreclause (PS * ps, int ocls)
+{
+  check_ready (ps);
+  check_unsat_state (ps);
+
+  ABORTIF (ocls < 0, "API usage: negative original clause index");
+  ABORTIF (ocls >= (int)ps->oadded, "API usage: original clause index exceeded");
+
+  assert (ps->mtcls || ps->failed_assumption);
+
+#ifdef TRACE
+  {
+    Cls ** clsptr, * c;
+    int res  = 0;
+
+    ABORTIF (!ps->trace, "tracing disabled");
+    if (ps->measurealltimeinlib)
+      enter (ps);
+    core (ps);
+    clsptr = ps->oclauses + ocls;
+    assert (clsptr < ps->ohead);
+    c = *clsptr;
+    if (c) 
+      res = c->core;
+    if (ps->measurealltimeinlib)
+      leave (ps);
+
+    return res;
+  }
+#else
+  ABORT ("compiled without trace support");
+  return 0;
+#endif
+}
+
+int
+picosat_failed_assumption (PS * ps, int int_lit)
+{
+  Lit * lit;
+  Var * v;
+  ABORTIF (!int_lit, "API usage: zero literal as assumption");
+  check_ready (ps);
+  check_unsat_state (ps);
+  if (ps->mtcls)
+    return 0;
+  assert (ps->failed_assumption);
+  if (abs (int_lit) > (int) ps->max_var)
+    return 0;
+  if (!ps->extracted_all_failed_assumptions)
+    extract_all_failed_assumptions (ps);
+  lit = import_lit (ps, int_lit, 1);
+  v = LIT2VAR (lit);
+  return v->failed;
+}
+
+int
+picosat_failed_context (PS * ps, int int_lit)
+{
+  Lit * lit;
+  Var * v;
+  ABORTIF (!int_lit, "API usage: zero literal as context");
+  ABORTIF (abs (int_lit) > (int) ps->max_var, "API usage: invalid context");
+  check_ready (ps);
+  check_unsat_state (ps);
+  assert (ps->failed_assumption);
+  if (!ps->extracted_all_failed_assumptions)
+    extract_all_failed_assumptions (ps);
+  lit = import_lit (ps, int_lit, 0);
+  v = LIT2VAR (lit);
+  return v->failed;
+}
+
+const int *
+picosat_failed_assumptions (PS * ps)
+{
+  Lit ** p, * lit;
+  Var * v;
+  int ilit;
+
+  ps->falshead = ps->fals;
+  check_ready (ps);
+  check_unsat_state (ps);
+  if (!ps->mtcls) 
+    {
+      assert (ps->failed_assumption);
+      if (!ps->extracted_all_failed_assumptions)
+	extract_all_failed_assumptions (ps);
+
+      for (p = ps->als; p < ps->alshead; p++)
+	{
+	  lit = *p;
+	  v = LIT2VAR (*p);
+	  if (!v->failed)
+	    continue;
+	  ilit = LIT2INT (lit);
+	  if (ps->falshead == ps->eofals)
+	    ENLARGE (ps->fals, ps->falshead, ps->eofals);
+	  *ps->falshead++ = ilit;
+	}
+    }
+  if (ps->falshead == ps->eofals)
+    ENLARGE (ps->fals, ps->falshead, ps->eofals);
+  *ps->falshead++ = 0;
+  return ps->fals;
+}
+
+const int *
+picosat_mus_assumptions (PS * ps, void * s, void (*cb)(void*,const int*), int fix)
+{
+  int i, j, ilit, len, nwork, * work, res;
+  signed char * redundant;
+  Lit ** p, * lit;
+  int failed;
+  Var * v;
+#ifndef NDEBUG
+  int oldlen;
+#endif
+#ifndef RCODE
+  int norig = ps->alshead - ps->als; 
+#endif
+
+  check_ready (ps);
+  check_unsat_state (ps);
+  len = 0;
+  if (!ps->mtcls) 
+    {
+      assert (ps->failed_assumption);
+      if (!ps->extracted_all_failed_assumptions)
+	extract_all_failed_assumptions (ps);
+
+      for (p = ps->als; p < ps->alshead; p++)
+	if (LIT2VAR (*p)->failed)
+	  len++;
+    }
+
+  if (ps->mass)
+    DELETEN (ps->mass, ps->szmass);
+  ps->szmass = len + 1;
+  NEWN (ps->mass, ps->szmass);
+
+  i = 0;
+  for (p = ps->als; p < ps->alshead; p++)
+    {
+      lit = *p;
+      v = LIT2VAR (lit);
+      if (!v->failed)
+	continue;
+      ilit = LIT2INT (lit);
+      assert (i < len);
+      ps->mass[i++] = ilit;
+    }
+  assert (i == len);
+  ps->mass[i] = 0;
+  if (ps->verbosity)
+     fprintf (ps->out, 
+      "%sinitial set of failed assumptions of size %d out of %d (%.0f%%)\n",
+      ps->prefix, len, norig, PERCENT (len, norig));
+  if (cb)
+    cb (s, ps->mass);
+
+  nwork = len;
+  NEWN (work, nwork);
+  for (i = 0; i < len; i++)
+    work[i] = ps->mass[i];
+
+  NEWN (redundant, nwork);
+  CLRN (redundant, nwork);
+
+  for (i = 0; i < nwork; i++)
+    {
+      if (redundant[i])
+	continue;
+
+      if (ps->verbosity > 1)
+	 fprintf (ps->out,
+	         "%strying to drop %d%s assumption %d\n", 
+		 ps->prefix, i, enumstr (i), work[i]);
+      for (j = 0; j < nwork; j++)
+	{
+	  if (i == j) continue;
+	  if (j < i && fix) continue;
+	  if (redundant[j]) continue;
+	  picosat_assume (ps, work[j]);
+	}
+
+      res = picosat_sat (ps, -1);
+      if (res == 10)
+	{
+	  if (ps->verbosity > 1)
+	     fprintf (ps->out,
+		     "%sfailed to drop %d%s assumption %d\n", 
+		     ps->prefix, i, enumstr (i), work[i]);
+
+	  if (fix)
+	    {
+	      picosat_add (ps, work[i]);
+	      picosat_add (ps, 0);
+	    }
+	}
+      else
+	{
+	  assert (res == 20);
+	  if (ps->verbosity > 1)
+	     fprintf (ps->out,
+		     "%ssuceeded to drop %d%s assumption %d\n", 
+		     ps->prefix, i, enumstr (i), work[i]);
+	  redundant[i] = 1;
+	  for (j = 0; j < nwork; j++)
+	    {
+	      failed = picosat_failed_assumption (ps, work[j]);
+	      if (j <= i) 
+		{
+		  assert ((j < i && fix) || redundant[j] == !failed);
+		  continue;
+		}
+
+	      if (!failed)
+		{
+		  redundant[j] = -1;
+		  if (ps->verbosity > 1)
+		     fprintf (ps->out,
+			     "%salso suceeded to drop %d%s assumption %d\n", 
+			     ps->prefix, j, enumstr (j), work[j]);
+		}
+	    }
+
+#ifndef NDEBUG
+	    oldlen = len;
+#endif
+	    len = 0;
+	    for (j = 0; j < nwork; j++)
+	      if (!redundant[j])
+		ps->mass[len++] = work[j];
+	    ps->mass[len] = 0;
+	    assert (len < oldlen);
+
+	    if (fix)
+	      {
+		picosat_add (ps, -work[i]);
+		picosat_add (ps, 0);
+	      }
+
+#ifndef NDEBUG
+	    for (j = 0; j <= i; j++)
+	      assert (redundant[j] >= 0);
+#endif
+	    for (j = i + 1; j < nwork; j++) 
+	      {
+		if (redundant[j] >= 0)
+		  continue;
+
+		if (fix)
+		  {
+		    picosat_add (ps, -work[j]);
+		    picosat_add (ps, 0);
+		  }
+
+		redundant[j] = 1;
+	      }
+
+	    if (ps->verbosity)
+	       fprintf (ps->out, 
+	"%sreduced set of failed assumptions of size %d out of %d (%.0f%%)\n",
+		ps->prefix, len, norig, PERCENT (len, norig));
+	    if (cb)
+	      cb (s, ps->mass);
+	}
+    }
+
+  DELETEN (work, nwork);
+  DELETEN (redundant, nwork);
+
+  if (ps->verbosity)
+    {
+       fprintf (ps->out, "%sreinitializing unsat state\n", ps->prefix);
+      fflush (ps->out);
+    }
+
+  for (i = 0; i < len; i++)
+    picosat_assume (ps, ps->mass[i]);
+
+#ifndef NDEBUG
+  res = 
+#endif
+  picosat_sat (ps, -1);
+  assert (res == 20);
+
+  if (!ps->mtcls)
+    {
+      assert (!ps->extracted_all_failed_assumptions);
+      extract_all_failed_assumptions (ps);
+    }
+
+  return ps->mass;
+}
+
+static const int *
+mss (PS * ps, int * a, int size)
+{
+  int i, j, k, res;
+
+  assert (!ps->mtcls);
+
+  if (ps->szmssass)
+    DELETEN (ps->mssass, ps->szmssass);
+
+  ps->szmssass = 0;
+  ps->mssass = 0;
+
+  ps->szmssass = size + 1;
+  NEWN (ps->mssass, ps->szmssass);
+
+  LOG ( fprintf (ps->out, "%ssearch MSS over %d assumptions\n", ps->prefix, size));
+
+  k = 0;
+  for (i = k; i < size; i++)
+    {
+      for (j = 0; j < k; j++)
+	picosat_assume (ps, ps->mssass[j]);
+
+      LOG ( fprintf (ps->out, 
+             "%strying to add assumption %d to MSS : %d\n", 
+	     ps->prefix, i, a[i])); 
+
+      picosat_assume (ps, a[i]);
+
+      res = picosat_sat (ps, -1);
+      if (res == 10)
+	{
+	  LOG ( fprintf (ps->out, 
+		 "%sadding assumption %d to MSS : %d\n", ps->prefix, i, a[i])); 
+
+	  ps->mssass[k++] = a[i];
+
+	  for (j = i + 1; j < size; j++)
+	    {
+	      if (picosat_deref (ps, a[j]) <= 0)
+		continue;
+
+	      LOG ( fprintf (ps->out, 
+		     "%salso adding assumption %d to MSS : %d\n", 
+		     ps->prefix, j, a[j])); 
+
+	      ps->mssass[k++] = a[j];
+
+	      if (++i != j)
+		{
+		  int tmp = a[i];
+		  a[i] = a[j];
+		  a[j] = tmp;
+		}
+	    }
+	}
+      else
+	{
+	  assert (res == 20);
+
+	  LOG ( fprintf (ps->out, 
+		 "%signoring assumption %d in MSS : %d\n", ps->prefix, i, a[i])); 
+	}
+    }
+  ps->mssass[k] = 0;
+  LOG ( fprintf (ps->out, "%sfound MSS of size %d\n", ps->prefix, k));
+
+  return ps->mssass;
+}
+
+static void
+reassume (PS * ps, const int * a, int size)
+{
+  int i;
+  LOG ( fprintf (ps->out, "%sreassuming all assumptions\n", ps->prefix));
+  for (i = 0; i < size; i++)
+    picosat_assume (ps, a[i]);
+}
+
+const int *
+picosat_maximal_satisfiable_subset_of_assumptions (PS * ps)
+{
+  const int * res;
+  int i, *a, size;
+
+  ABORTIF (ps->mtcls,
+           "API usage: CNF inconsistent (use 'picosat_inconsistent')");
+
+  enter (ps);
+
+  size = ps->alshead - ps->als;
+  NEWN (a, size);
+
+  for (i = 0; i < size; i++)
+    a[i] = LIT2INT (ps->als[i]);
+
+  res = mss (ps, a, size);
+  reassume (ps, a, size);
+
+  DELETEN (a, size);
+
+  leave (ps);
+
+  return res;
+}
+
+static void
+check_mss_flags_clean (PS * ps)
+{
+#ifndef NDEBUG
+  unsigned i;
+  for (i = 1; i <= ps->max_var; i++)
+    {
+      assert (!ps->vars[i].msspos);
+      assert (!ps->vars[i].mssneg);
+    }
+#else
+  (void) ps;
+#endif
+}
+
+static void
+push_mcsass (PS * ps, int lit)
+{
+  if (ps->nmcsass == ps->szmcsass)
+    {
+      ps->szmcsass = ps->szmcsass ? 2*ps->szmcsass : 1;
+      RESIZEN (ps->mcsass, ps->nmcsass, ps->szmcsass);
+    }
+
+  ps->mcsass[ps->nmcsass++] = lit;
+}
+
+static const int *
+next_mss (PS * ps, int mcs)
+{
+  int i, *a, size, mssize, mcsize, lit, inmss;
+  const int * res, * p;
+  Var * v;
+
+  if (ps->mtcls) return 0;
+
+  check_mss_flags_clean (ps);
+
+  if (mcs && ps->mcsass)
+    {
+      DELETEN (ps->mcsass, ps->szmcsass);
+      ps->nmcsass = ps->szmcsass = 0;
+      ps->mcsass = 0;
+    }
+
+  size = ps->alshead - ps->als;
+  NEWN (a, size);
+
+  for (i = 0; i < size; i++)
+    a[i] = LIT2INT (ps->als[i]);
+
+  (void) picosat_sat (ps, -1);
+
+  //TODO short cut for 'picosat_res () == 10'?
+
+  if (ps->mtcls)
+    {
+      assert (picosat_res (ps) == 20);
+      res = 0;
+      goto DONE;
+    }
+
+  res = mss (ps, a, size);
+
+  if (ps->mtcls)
+    {
+      res = 0;
+      goto DONE;
+    }
+
+  for (p = res; (lit = *p); p++) 
+    {
+      v = ps->vars + abs (lit);
+      if (lit < 0)
+	{
+	  assert (!v->msspos);
+	  v->mssneg = 1;
+	}
+      else
+	{
+	  assert (!v->mssneg);
+	  v->msspos = 1;
+	}
+    }
+
+  mssize = p - res;
+  mcsize = INT_MIN;
+
+  for (i = 0; i < size; i++)
+    {
+      lit = a[i];
+      v = ps->vars + abs (lit);
+      if (lit > 0 && v->msspos)
+	inmss = 1;
+      else if (lit < 0 && v->mssneg)
+	inmss = 1;
+      else 
+	inmss = 0;
+
+      if (mssize < mcsize)
+	{
+	  if (inmss)
+	    picosat_add (ps, -lit);
+	}
+      else
+	{
+	  if (!inmss)
+	    picosat_add (ps, lit);
+	}
+
+      if (!inmss && mcs)
+	push_mcsass (ps, lit);
+    }
+  picosat_add (ps, 0);
+  if (mcs)
+    push_mcsass (ps, 0);
+
+  for (i = 0; i < size; i++)
+    {
+      lit = a[i];
+      v = ps->vars + abs (lit);
+      v->msspos = 0;
+      v->mssneg = 0;
+    }
+
+DONE:
+
+  reassume (ps, a, size);
+  DELETEN (a, size);
+
+  return res;
+}
+
+const int *
+picosat_next_maximal_satisfiable_subset_of_assumptions (PS * ps)
+{
+  const int * res;
+  enter (ps);
+  res = next_mss (ps, 0);
+  leave (ps);
+  return  res;
+}
+
+const int *
+picosat_next_minimal_correcting_subset_of_assumptions (PS * ps)
+{
+  const int * res, * tmp;
+  enter (ps);
+  tmp = next_mss (ps, 1);
+  res = tmp ? ps->mcsass : 0;
+  leave (ps);
+  return res;
+}
+
+const int *
+picosat_humus (PS * ps, 
+               void (*callback)(void*state,int nmcs,int nhumus),
+	       void * state)
+{
+  int lit, nmcs, j, nhumus;
+  const int * mcs, * p;
+  unsigned i;
+  Var * v;
+  enter (ps);
+#ifndef NDEBUG
+  for (i = 1; i <= ps->max_var; i++)
+    {
+      v = ps->vars + i;
+      assert (!v->humuspos);
+      assert (!v->humusneg);
+    }
+#endif
+  nhumus = nmcs = 0;
+  while ((mcs = picosat_next_minimal_correcting_subset_of_assumptions (ps)))
+    {
+      for (p = mcs; (lit = *p); p++)
+	{
+	  v = ps->vars + abs (lit);
+	  if (lit < 0)
+	    {
+	      if (!v->humusneg)
+		{
+		  v->humusneg = 1;
+		  nhumus++;
+		}
+	    }
+	  else
+	    {
+	      if (!v->humuspos)
+		{
+		  v->humuspos = 1;
+		  nhumus++;
+		}
+	    }
+	}
+      nmcs++;
+      LOG ( fprintf (ps->out, 
+             "%smcs %d of size %d humus %d\n",
+	     ps->prefix, nmcs, (int)(p - mcs), nhumus));
+      if (callback)
+	callback (state, nmcs, nhumus);
+    }
+  assert (!ps->szhumus);
+  ps->szhumus = 1;
+  for (i = 1; i <= ps->max_var; i++)
+    {
+      v = ps->vars + i;
+      if (v->humuspos)
+	ps->szhumus++;
+      if (v->humusneg)
+	ps->szhumus++;
+    }
+  assert (nhumus + 1 == ps->szhumus);
+  NEWN (ps->humus, ps->szhumus);
+  j = 0;
+  for (i = 1; i <= ps->max_var; i++)
+    {
+      v = ps->vars + i;
+      if (v->humuspos)
+	{
+	  assert (j < nhumus);
+	  ps->humus[j++] = (int) i;
+	}
+      if (v->humusneg)
+	{
+	  assert (j < nhumus);
+	  assert (i < INT_MAX);
+	  ps->humus[j++] = - (int) i;
+	}
+    }
+  assert (j == nhumus);
+  assert (j < ps->szhumus);
+  ps->humus[j] = 0;
+  leave (ps);
+  return ps->humus;
+}
+
+int
+picosat_usedlit (PS * ps, int int_lit)
+{
+  int res;
+  check_ready (ps);
+  check_sat_or_unsat_or_unknown_state (ps);
+  ABORTIF (!int_lit, "API usage: zero literal can not be used");
+  int_lit = abs (int_lit);
+  res = (int_lit <= (int) ps->max_var) ? ps->vars[int_lit].used : 0;
+  return res;
+}
+
+void
+picosat_write_clausal_core (PS * ps, FILE * file)
+{
+  check_trace_support_and_execute (ps, file, write_core_wrapper, 0);
+}
+
+void
+picosat_write_compact_trace (PS * ps, FILE * file)
+{
+  check_trace_support_and_execute (ps, file, write_trace,
+                                   COMPACT_TRACECHECK_TRACE_FMT);
+}
+
+void
+picosat_write_extended_trace (PS * ps, FILE * file)
+{
+  check_trace_support_and_execute (ps, file, write_trace,
+                                   EXTENDED_TRACECHECK_TRACE_FMT);
+}
+
+void
+picosat_write_rup_trace (PS * ps, FILE * file)
+{
+  check_trace_support_and_execute (ps, file, write_trace, RUP_TRACE_FMT);
+}
+
+size_t
+picosat_max_bytes_allocated (PS * ps)
+{
+  check_ready (ps);
+  return ps->max_bytes;
+}
+
+void
+picosat_set_propagation_limit (PS * ps, unsigned long long l)
+{
+  ps->lpropagations = l;
+}
+
+unsigned long long
+picosat_propagations (PS * ps)
+{
+  return ps->propagations;
+}
+
+unsigned long long
+picosat_visits (PS * ps)
+{
+  return ps->visits;
+}
+
+unsigned long long
+picosat_decisions (PS * ps)
+{
+  return ps->decisions;
+}
+
+int
+picosat_variables (PS * ps)
+{
+  check_ready (ps);
+  return (int) ps->max_var;
+}
+
+int
+picosat_added_original_clauses (PS * ps)
+{
+  check_ready (ps);
+  return (int) ps->oadded;
+}
+
+void
+picosat_stats (PS * ps)
+{
+#ifndef RCODE
+  unsigned redlits;
+#endif
+#ifdef STATS
+  check_ready (ps);
+  assert (ps->sdecisions + ps->rdecisions + ps->assumptions == ps->decisions);
+#endif
+  if (ps->calls > 1)
+     fprintf (ps->out, "%s%u calls\n", ps->prefix, ps->calls);
+  if (ps->contexts)
+    {
+       fprintf (ps->out, "%s%u contexts", ps->prefix, ps->contexts);
+#ifdef STATS
+       fprintf (ps->out, " %u internal variables", ps->internals);
+#endif
+       fprintf (ps->out, "\n");
+    }
+   fprintf (ps->out, "%s%u iterations\n", ps->prefix, ps->iterations);
+   fprintf (ps->out, "%s%u restarts", ps->prefix, ps->restarts);
+#ifdef STATS
+   fprintf (ps->out, " (%u skipped)", ps->skippedrestarts);
+#endif
+  fputc ('\n', ps->out);
+#ifndef NFL
+   fprintf (ps->out, "%s%u failed literals", ps->prefix, ps->failedlits);
+#ifdef STATS
+   fprintf (ps->out,
+           ", %u calls, %u rounds, %llu propagations",
+           ps->flcalls, ps->flrounds, ps->flprops);
+#endif
+  fputc ('\n', ps->out);
+#ifdef STATS
+   fprintf (ps->out, 
+    "%sfl: %u = %.1f%% implicit, %llu oopsed, %llu tried, %llu skipped\n", 
+    ps->prefix, 
+    ps->ifailedlits, PERCENT (ps->ifailedlits, ps->failedlits),
+    ps->floopsed, ps->fltried, ps->flskipped);
+#endif
+#endif
+   fprintf (ps->out, "%s%u conflicts", ps->prefix, ps->conflicts);
+#ifdef STATS
+   fprintf (ps->out, " (%u uips = %.1f%%)\n", ps->uips, PERCENT(ps->uips,ps->conflicts));
+#else
+  fputc ('\n', ps->out);
+#endif
+#ifndef NADC
+   fprintf (ps->out, "%s%u adc conflicts\n", ps->prefix, ps->adoconflicts);
+#endif
+#ifdef STATS
+   fprintf (ps->out, "%s%llu dereferenced literals\n", ps->prefix, ps->derefs);
+#endif
+   fprintf (ps->out, "%s%u decisions", ps->prefix, ps->decisions);
+#ifdef STATS
+   fprintf (ps->out, " (%u random = %.2f%%",
+           ps->rdecisions, PERCENT (ps->rdecisions, ps->decisions));
+   fprintf (ps->out, ", %u assumptions", ps->assumptions);
+  fputc (')', ps->out);
+#endif
+  fputc ('\n', ps->out);
+#ifdef STATS
+   fprintf (ps->out,
+           "%s%u static phase decisions (%.1f%% of all variables)\n",
+	   ps->prefix,
+	   ps->staticphasedecisions, PERCENT (ps->staticphasedecisions, ps->max_var));
+#endif
+   fprintf (ps->out, "%s%u fixed variables\n", ps->prefix, ps->fixed);
+  assert (ps->nonminimizedllits >= ps->minimizedllits);
+#ifndef RCODE
+  redlits = ps->nonminimizedllits - ps->minimizedllits;
+#endif
+   fprintf (ps->out, "%s%u learned literals\n", ps->prefix, ps->llitsadded);
+   fprintf (ps->out, "%s%.1f%% deleted literals\n",
+     ps->prefix, PERCENT (redlits, ps->nonminimizedllits));
+
+#ifdef STATS
+#ifdef TRACE
+   fprintf (ps->out,
+	   "%s%llu antecedents (%.1f antecedents per clause",
+	   ps->prefix, ps->antecedents, AVERAGE (ps->antecedents, ps->conflicts));
+  if (ps->trace)
+     fprintf (ps->out, ", %.1f bytes/antecedent)", AVERAGE (ps->znts, ps->antecedents));
+  fputs (")\n", ps->out);
+#endif
+
+   fprintf (ps->out, "%s%llu propagations (%.1f propagations per decision)\n",
+           ps->prefix, ps->propagations, AVERAGE (ps->propagations, ps->decisions));
+   fprintf (ps->out, "%s%llu visits (%.1f per propagation)\n",
+	   ps->prefix, ps->visits, AVERAGE (ps->visits, ps->propagations));
+   fprintf (ps->out, 
+           "%s%llu binary clauses visited (%.1f%% %.1f per propagation)\n",
+	   ps->prefix, ps->bvisits, 
+	   PERCENT (ps->bvisits, ps->visits),
+	   AVERAGE (ps->bvisits, ps->propagations));
+   fprintf (ps->out, 
+           "%s%llu ternary clauses visited (%.1f%% %.1f per propagation)\n",
+	   ps->prefix, ps->tvisits, 
+	   PERCENT (ps->tvisits, ps->visits),
+	   AVERAGE (ps->tvisits, ps->propagations));
+   fprintf (ps->out, 
+           "%s%llu large clauses visited (%.1f%% %.1f per propagation)\n",
+	   ps->prefix, ps->lvisits, 
+	   PERCENT (ps->lvisits, ps->visits),
+	   AVERAGE (ps->lvisits, ps->propagations));
+   fprintf (ps->out, "%s%llu other true (%.1f%% of visited clauses)\n",
+	   ps->prefix, ps->othertrue, PERCENT (ps->othertrue, ps->visits));
+   fprintf (ps->out, 
+           "%s%llu other true in binary clauses (%.1f%%)"
+	   ", %llu upper (%.1f%%)\n",
+           ps->prefix, ps->othertrue2, PERCENT (ps->othertrue2, ps->othertrue),
+	   ps->othertrue2u, PERCENT (ps->othertrue2u, ps->othertrue2));
+   fprintf (ps->out, 
+           "%s%llu other true in large clauses (%.1f%%)"
+	   ", %llu upper (%.1f%%)\n",
+           ps->prefix, ps->othertruel, PERCENT (ps->othertruel, ps->othertrue),
+	   ps->othertruelu, PERCENT (ps->othertruelu, ps->othertruel));
+   fprintf (ps->out, "%s%llu ternary and large traversals (%.1f per visit)\n",
+	   ps->prefix, ps->traversals, AVERAGE (ps->traversals, ps->visits));
+   fprintf (ps->out, "%s%llu large traversals (%.1f per large visit)\n",
+	   ps->prefix, ps->ltraversals, AVERAGE (ps->ltraversals, ps->lvisits));
+   fprintf (ps->out, "%s%llu assignments\n", ps->prefix, ps->assignments);
+#else
+   fprintf (ps->out, "%s%llu propagations\n", ps->prefix, picosat_propagations (ps));
+   fprintf (ps->out, "%s%llu visits\n", ps->prefix, picosat_visits (ps));
+#endif
+   fprintf (ps->out, "%s%.1f%% variables used\n", ps->prefix, PERCENT (ps->vused, ps->max_var));
+
+  sflush (ps);
+   fprintf (ps->out, "%s%.1f seconds in library\n", ps->prefix, ps->seconds);
+   fprintf (ps->out, "%s%.1f megaprops/second\n",
+	   ps->prefix, AVERAGE (ps->propagations / 1e6f, ps->seconds));
+   fprintf (ps->out, "%s%.1f megavisits/second\n",
+	   ps->prefix, AVERAGE (ps->visits / 1e6f, ps->seconds));
+   fprintf (ps->out, "%sprobing %.1f seconds %.0f%%\n",
+           ps->prefix, ps->flseconds, PERCENT (ps->flseconds, ps->seconds));
+#ifdef STATS
+   fprintf (ps->out,
+	   "%srecycled %.1f MB in %u reductions\n",
+	   ps->prefix, ps->rrecycled / (double) (1 << 20), ps->reductions);
+   fprintf (ps->out,
+	   "%srecycled %.1f MB in %u simplifications\n",
+	   ps->prefix, ps->srecycled / (double) (1 << 20), ps->simps);
+#else
+   fprintf (ps->out, "%s%u simplifications\n", ps->prefix, ps->simps);
+   fprintf (ps->out, "%s%u reductions\n", ps->prefix, ps->reductions);
+   fprintf (ps->out, "%s%.1f MB recycled\n", ps->prefix, ps->recycled / (double) (1 << 20));
+#endif
+   fprintf (ps->out, "%s%.1f MB maximally allocated\n",
+	    ps->prefix, picosat_max_bytes_allocated (ps) / (double) (1 << 20));
+}
+
+#ifndef NGETRUSAGE
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/unistd.h>
+#endif
+
+double
+picosat_time_stamp (void)
+{
+  double res = -1;
+#ifndef NGETRUSAGE
+  struct rusage u;
+  res = 0;
+  if (!getrusage (RUSAGE_SELF, &u))
+    {
+      res += u.ru_utime.tv_sec + 1e-6 * u.ru_utime.tv_usec;
+      res += u.ru_stime.tv_sec + 1e-6 * u.ru_stime.tv_usec;
+    }
+#endif
+  return res;
+}
+
+double
+picosat_seconds (PS * ps)
+{
+  check_ready (ps);
+  return ps->seconds;
+}
+
+void
+picosat_print (PS * ps, FILE * file)
+{
+#ifdef NO_BINARY_CLAUSES
+  Lit * lit, *other, * last;
+  Ltk * stack;
+#endif
+  Lit **q, **eol;
+  Cls **p, *c;
+  unsigned n;
+
+  if (ps->measurealltimeinlib)
+    enter (ps);
+  else
+    check_ready (ps);
+
+  n = 0;
+  n +=  ps->alshead - ps->als;
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+
+      if (!c)
+	continue;
+
+#ifdef TRACE
+      if (c->collected)
+	continue;
+#endif
+      n++;
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  last = int2lit (ps, -ps->max_var);
+  for (lit = int2lit (ps, 1); lit <= last; lit++)
+    {
+      stack = LIT2IMPLS (lit);
+      eol = stack->start + stack->count;
+      for (q = stack->start; q < eol; q++)
+	if (*q >= lit)
+	  n++;
+    }
+#endif
+
+  fprintf (file, "p cnf %d %u\n", ps->max_var, n);
+
+  for (p = SOC; p != EOC; p = NXC (p))
+    {
+      c = *p;
+      if (!c)
+	continue;
+
+#ifdef TRACE
+      if (c->collected)
+	continue;
+#endif
+
+      eol = end_of_lits (c);
+      for (q = c->lits; q < eol; q++)
+	fprintf (file, "%d ", LIT2INT (*q));
+
+      fputs ("0\n", file);
+    }
+
+#ifdef NO_BINARY_CLAUSES
+  last = int2lit (ps, -ps->max_var);
+  for (lit = int2lit (ps, 1); lit <= last; lit++)
+    {
+      stack = LIT2IMPLS (lit);
+      eol = stack->start + stack->count;
+      for (q = stack->start; q < eol; q++)
+	if ((other = *q) >= lit)
+	  fprintf (file, "%d %d 0\n", LIT2INT (lit), LIT2INT (other));
+    }
+#endif
+
+  {
+    Lit **r;
+    for (r = ps->als; r < ps->alshead; r++)
+      fprintf (file, "%d 0\n", LIT2INT (*r));
+  }
+
+  fflush (file);
+
+  if (ps->measurealltimeinlib)
+    leave (ps);
+}
+
+void
+picosat_enter (PS * ps)
+{
+  enter (ps);
+}
+
+void
+picosat_leave (PS * ps)
+{
+  leave (ps);
+}
+
+void
+picosat_message (PS * ps, int vlevel, const char * fmt, ...)
+{
+  va_list ap;
+
+  if (vlevel > ps->verbosity)
+    return;
+
+  fputs (ps->prefix, ps->out);
+  va_start (ap, fmt);
+  vfprintf (ps->out, fmt, ap);
+  va_end (ap);
+  fputc ('\n', ps->out);
+}
+
+int
+picosat_changed (PS * ps)
+{
+  int res;
+
+  check_ready (ps);
+  check_sat_state (ps);
+
+  res = (ps->min_flipped <= ps->saved_max_var);
+  assert (!res || ps->saved_flips != ps->flips);
+
+  return res;
+}
+
+void
+picosat_reset_phases (PS * ps)
+{
+  rebias (ps);
+}
+
+void
+picosat_reset_scores (PS * ps)
+{
+  Rnk * r;
+  ps->hhead = ps->heap + 1;
+  for (r = ps->rnks + 1; r <= ps->rnks + ps->max_var; r++)
+    {
+      CLR (r);
+      hpush (ps, r);
+    }
+}
+
+void
+picosat_remove_learned (PS * ps, unsigned percentage)
+{
+  enter (ps);
+  reset_incremental_usage (ps);
+  reduce (ps, percentage);
+  leave (ps);
+}
+
+void
+picosat_set_global_default_phase (PS * ps, int phase)
+{
+  check_ready (ps);
+  ABORTIF (phase < 0, "API usage: 'picosat_set_global_default_phase' "
+                      "with negative argument");
+  ABORTIF (phase > 3, "API usage: 'picosat_set_global_default_phase' "
+                      "with argument > 3");
+  ps->defaultphase = phase;
+}
+
+void
+picosat_set_default_phase_lit (PS * ps, int int_lit, int phase)
+{
+  unsigned newphase;
+  Lit * lit;
+  Var * v;
+
+  check_ready (ps);
+
+  lit = import_lit (ps, int_lit, 1);
+  v = LIT2VAR (lit);
+
+  if (phase)
+    {
+      newphase = (int_lit < 0) == (phase < 0);
+      v->defphase = v->phase = newphase;
+      v->usedefphase = v->assigned = 1;
+    }
+  else
+    {
+      v->usedefphase = v->assigned = 0;
+    }
+}
+
+void
+picosat_set_more_important_lit (PS * ps, int int_lit)
+{
+  Lit * lit;
+  Var * v;
+  Rnk * r;
+
+  check_ready (ps);
+
+  lit = import_lit (ps, int_lit, 1);
+  v = LIT2VAR (lit);
+  r = VAR2RNK (v);
+
+  ABORTIF (r->lessimportant, "can not mark variable more and less important"); 
+
+  if (r->moreimportant)
+    return;
+
+  r->moreimportant = 1;
+
+  if (r->pos)
+    hup (ps, r);
+}
+
+void
+picosat_set_less_important_lit (PS * ps, int int_lit)
+{
+  Lit * lit;
+  Var * v;
+  Rnk * r;
+
+  check_ready (ps);
+
+  lit = import_lit (ps, int_lit, 1);
+  v = LIT2VAR (lit);
+  r = VAR2RNK (v);
+
+  ABORTIF (r->moreimportant, "can not mark variable more and less important"); 
+
+  if (r->lessimportant)
+    return;
+
+  r->lessimportant = 1;
+
+  if (r->pos)
+    hdown (ps, r);
+}
+
+#ifndef NADC
+
+unsigned 
+picosat_ado_conflicts (PS * ps)
+{
+  check_ready (ps);
+  return ps->adoconflicts;
+}
+
+void
+picosat_disable_ado (PS * ps)
+{
+  check_ready (ps);
+  assert (!ps->adodisabled);
+  ps->adodisabled = 1;
+}
+
+void
+picosat_enable_ado (PS * ps)
+{
+  check_ready (ps);
+  assert (ps->adodisabled);
+  ps->adodisabled = 0;
+}
+
+void
+picosat_set_ado_conflict_limit (PS * ps, unsigned newadoconflictlimit)
+{
+  check_ready (ps);
+  ps->adoconflictlimit = newadoconflictlimit;
+}
+
+#endif
+
+void
+picosat_simplify (PS * ps)
+{
+  enter (ps);
+  reset_incremental_usage (ps);
+  simplify (ps, 1);
+  leave (ps);
+}
+
+int
+picosat_haveados (void)
+{
+#ifndef NADC
+  return 1;
+#else
+  return 0;
+#endif
+}
+
+void
+picosat_save_original_clauses (PS * ps)
+{
+  if (ps->saveorig) return;
+  ABORTIF (ps->oadded, "API usage: 'picosat_save_original_clauses' too late");
+  ps->saveorig = 1;
+}
+
+void picosat_set_interrupt (PicoSAT * ps,
+                            void * external_state,
+			    int (*interrupted)(void * external_state)) 
+{
+  ps->interrupt.state = external_state;
+  ps->interrupt.function = interrupted;
+}
+
+int
+picosat_deref_partial (PS * ps, int int_lit) 
+{
+  check_ready (ps);
+  check_sat_state (ps);
+  ABORTIF (!int_lit, "API usage: can not partial deref zero literal");
+  ABORTIF (ps->mtcls, "API usage: deref partial after empty clause generated");
+  ABORTIF (!ps->saveorig, "API usage: 'picosat_save_original_clauses' missing");
+
+#ifdef STATS
+  ps->derefs++;
+#endif
+
+  if (!ps->partial)
+    minautarky (ps);
+
+  return pderef (ps, int_lit);
+}
diff --git a/test/picosat-965/picosat.h b/test/picosat-965/picosat.h
new file mode 100644
index 00000000..668bc00b
--- /dev/null
+++ b/test/picosat-965/picosat.h
@@ -0,0 +1,658 @@
+/****************************************************************************
+Copyright (c) 2006 - 2015, Armin Biere, Johannes Kepler University.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+****************************************************************************/
+
+#ifndef picosat_h_INCLUDED
+#define picosat_h_INCLUDED
+
+/*------------------------------------------------------------------------*/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+
+/*------------------------------------------------------------------------*/
+/* The following macros allows for users to distiguish between different
+ * versions of the API.  The first 'PICOSAT_REENTRANT_API' is defined for
+ * the new reentrant API which allows to generate multiple instances of
+ * PicoSAT in one process.  The second 'PICOSAT_API_VERSION' defines the
+ * (smallest) version of PicoSAT to which this API conforms.
+ */
+#define PICOSAT_REENTRANT_API
+#define PICOSAT_API_VERSION 953		/* API version */
+
+/*------------------------------------------------------------------------*/
+/* These are the return values for 'picosat_sat' as for instance
+ * standardized by the output format of the SAT competition.
+ */
+#define PICOSAT_UNKNOWN         0
+#define PICOSAT_SATISFIABLE     10
+#define PICOSAT_UNSATISFIABLE   20
+
+/*------------------------------------------------------------------------*/
+
+typedef struct PicoSAT PicoSAT;
+
+/*------------------------------------------------------------------------*/
+
+const char *picosat_version (void);
+const char *picosat_config (void);
+const char *picosat_copyright (void);
+
+/*------------------------------------------------------------------------*/
+/* You can make PicoSAT use an external memory manager instead of the one
+ * provided by LIBC. But then you need to call these three function before
+ * 'picosat_init'.  The memory manager functions here all have an additional
+ * first argument which is a pointer to the memory manager, but otherwise
+ * are supposed to work as their LIBC counter parts 'malloc', 'realloc' and
+ * 'free'.  As exception the 'resize' and 'delete' function have as third
+ * argument the number of bytes of the block given as second argument.
+ */
+
+typedef void * (*picosat_malloc)(void *, size_t);
+typedef void * (*picosat_realloc)(void*, void *, size_t, size_t);
+typedef void (*picosat_free)(void*, void*, size_t);
+
+/*------------------------------------------------------------------------*/
+
+PicoSAT * picosat_init (void);          /* constructor */
+
+PicoSAT * picosat_minit (void * state,
+			 picosat_malloc,
+			 picosat_realloc,
+			 picosat_free);
+
+void picosat_reset (PicoSAT *);         /* destructor */
+
+/*------------------------------------------------------------------------*/
+/* The following five functions are essentially parameters to 'init', and
+ * thus should be called right after 'picosat_init' before doing anything
+ * else.  You should not call any of them after adding a literal.
+ */
+
+/* Set output file, default is 'stdout'.
+ */
+void picosat_set_output (PicoSAT *, FILE *);
+
+/* Measure all time spent in all calls in the solver.  By default only the
+ * time spent in 'picosat_sat' is measured.  Enabling this function might
+ * for instance triple the time needed to add large CNFs, since every call
+ * to 'picosat_add' will trigger a call to 'getrusage'.
+ */
+void picosat_measure_all_calls (PicoSAT *);
+
+/* Set the prefix used for printing verbose messages and statistics.
+ * Default is "c ".
+ */
+void picosat_set_prefix (PicoSAT *, const char *);
+
+/* Set verbosity level.  A verbosity level of 1 and above prints more and
+ * more detailed progress reports on the output file, set by
+ * 'picosat_set_output'.  Verbose messages are prefixed with the string set
+ * by 'picosat_set_prefix'.
+ */
+void picosat_set_verbosity (PicoSAT *, int new_verbosity_level);
+
+/* Disable/Enable all pre-processing, currently only failed literal probing.
+ *
+ *  new_plain_value != 0    only 'plain' solving, so no preprocessing
+ *  new_plain_value == 0    allow preprocessing
+ */
+void picosat_set_plain (PicoSAT *, int new_plain_value);
+
+/* Set default initial phase: 
+ *
+ *   0 = false
+ *   1 = true
+ *   2 = Jeroslow-Wang (default)
+ *   3 = random initial phase
+ *
+ * After a variable has been assigned the first time, it will always
+ * be assigned the previous value if it is picked as decision variable.
+ * The initial assignment can be chosen with this function.
+ */
+void picosat_set_global_default_phase (PicoSAT *, int);
+
+/* Set next/initial phase of a particular variable if picked as decision
+ * variable.  Second argument 'phase' has the following meaning:
+ *
+ *   negative = next value if picked as decision variable is false
+ *
+ *   positive = next value if picked as decision variable is true
+ *
+ *   0        = use global default phase as next value and
+ *              assume 'lit' was never assigned
+ *
+ * Again if 'lit' is assigned afterwards through a forced assignment,
+ * then this forced assignment is the next phase if this variable is
+ * used as decision variable.
+ */
+void picosat_set_default_phase_lit (PicoSAT *, int lit, int phase);
+
+/* You can reset all phases by the following function.
+ */
+void picosat_reset_phases (PicoSAT *);
+
+/* Scores can be erased as well.  Note, however, that even after erasing 
+ * scores and phases, learned clauses are kept.  In addition head tail
+ * pointers for literals are not moved either.  So expect a difference
+ * between calling the solver in incremental mode or with a fresh copy of
+ * the CNF.
+ */
+void picosat_reset_scores (PicoSAT *);
+
+/* Reset assignment if in SAT state and then remove the given percentage of
+ * less active (large) learned clauses.  If you specify 100% all large
+ * learned clauses are removed.
+ */
+void picosat_remove_learned (PicoSAT *, unsigned percentage);
+
+/* Set some variables to be more important than others.  These variables are
+ * always used as decisions before other variables are used.  Dually there
+ * is a set of variables that is used last.  The default is
+ * to mark all variables as being indifferent only.
+ */
+void picosat_set_more_important_lit (PicoSAT *, int lit);
+void picosat_set_less_important_lit (PicoSAT *, int lit);
+
+/* Allows to print to internal 'out' file from client.
+ */
+void picosat_message (PicoSAT *, int verbosity_level, const char * fmt, ...);
+
+/* Set a seed for the random number generator.  The random number generator
+ * is currently just used for generating random decisions.  In our
+ * experiments having random decisions did not really help on industrial
+ * examples, but was rather helpful to randomize the solver in order to
+ * do proper benchmarking of different internal parameter sets.
+ */
+void picosat_set_seed (PicoSAT *, unsigned random_number_generator_seed);
+
+/* If you ever want to extract cores or proof traces with the current
+ * instance of PicoSAT initialized with 'picosat_init', then make sure to
+ * call 'picosat_enable_trace_generation' right after 'picosat_init'.   This
+ * is not necessary if you only use 'picosat_set_incremental_rup_file'.
+ *
+ * NOTE, trace generation code is not necessarily included, e.g. if you
+ * configure PicoSAT with full optimzation as './configure.sh -O' or with
+ 
+ * you do not get any results by trying to generate traces.
+ *
+ * The return value is non-zero if code for generating traces is included
+ * and it is zero if traces can not be generated.
+ */
+int picosat_enable_trace_generation (PicoSAT *);
+
+/* You can dump proof traces in RUP format incrementally even without
+ * keeping the proof trace in memory.  The advantage is a reduction of
+ * memory usage, but the dumped clauses do not necessarily belong to the
+ * clausal core.  Beside the file the additional parameters denotes the
+ * maximal number of variables and the number of original clauses.
+ */
+void picosat_set_incremental_rup_file (PicoSAT *, FILE * file, int m, int n);
+
+/* Save original clauses for 'picosat_deref_partial'.  See comments to that
+ * function further down.
+ */
+void picosat_save_original_clauses (PicoSAT *);
+
+/* Add a call back which is checked regularly to notify the SAT solver
+ * to terminate earlier.  This is useful for setting external time limits
+ * or terminate early in say a portfolio style parallel SAT solver.
+ */
+void picosat_set_interrupt (PicoSAT *,
+                            void * external_state,
+			    int (*interrupted)(void * external_state));
+
+/*------------------------------------------------------------------------*/
+/* This function returns the next available unused variable index and
+ * allocates a variable for it even though this variable does not occur as
+ * assumption, nor in a clause or any other constraints.  In future calls to
+ * 'picosat_sat', 'picosat_deref' and particularly for 'picosat_changed',
+ * this variable is treated as if it had been used.
+ */
+int picosat_inc_max_var (PicoSAT *);
+
+/*------------------------------------------------------------------------*/
+/* Push and pop semantics for PicoSAT.   'picosat_push' opens up a new
+ * context.  All clauses added in this context are attached to it and
+ * discarded when the context is closed with 'picosat_pop'.  It is also
+ * possible to nest contexts.
+ *
+ * The current implementation uses a new internal variable for each context.
+ * However, the indices for these internal variables are shared with
+ * ordinary external variables.  This means that after any call to
+ * 'picosat_push', new variable indices should be obtained with
+ * 'picosat_inc_max_var' and not just by incrementing the largest variable
+ * index used so far.
+ *
+ * The return value is the index of the literal that assumes this context.
+ * This literal can only be used for 'picosat_failed_context' otherwise
+ * it will lead to an API usage error.
+ */
+int picosat_push (PicoSAT *);
+
+/* This is as 'picosat_failed_assumption', but only for internal variables
+ * generated by 'picosat_push'.
+ */
+int picosat_failed_context (PicoSAT *, int lit);
+
+/* Returns the literal that assumes the current context or zero if the
+ * outer context has been reached.
+ */
+int picosat_context (PicoSAT *);	
+
+/* Closes the current context and recycles the literal generated for
+ * assuming this context.  The return value is the literal for the new
+ * outer context or zero if the outer most context has been reached.
+ */
+int picosat_pop (PicoSAT *);
+
+/* Force immmediate removal of all satisfied clauses and clauses that are
+ * added or generated in closed contexts.  This function is called
+ * internally if enough units are learned or after a certain number of
+ * contexts have been closed.  This number is fixed at compile time
+ * and defined as MAXCILS in 'picosat.c'.
+ *
+ * Note that learned clauses which only involve outer contexts are kept.
+ */
+void picosat_simplify (PicoSAT *);
+
+/*------------------------------------------------------------------------*/
+/* If you know a good estimate on how many variables you are going to use
+ * then calling this function before adding literals will result in less
+ * resizing of the variable table.  But this is just a minor optimization.
+ * Beside exactly allocating enough variables it has the same effect as
+ * calling 'picosat_inc_max_var'.
+ */
+void picosat_adjust (PicoSAT *, int max_idx);
+
+/*------------------------------------------------------------------------*/
+/* Statistics.
+ */
+int picosat_variables (PicoSAT *);                      /* p cnf <m> n */
+int picosat_added_original_clauses (PicoSAT *);         /* p cnf m <n> */
+size_t picosat_max_bytes_allocated (PicoSAT *);
+double picosat_time_stamp (void);                       /* ... in process */
+void picosat_stats (PicoSAT *);                         /* > output file */
+unsigned long long picosat_propagations (PicoSAT *);	/* #propagations */
+unsigned long long picosat_decisions (PicoSAT *);	/* #decisions */
+unsigned long long picosat_visits (PicoSAT *);		/* #visits */
+
+/* The time spent in calls to the library or in 'picosat_sat' respectively.
+ * The former is returned if, right after initialization
+ * 'picosat_measure_all_calls' is called.
+ */
+double picosat_seconds (PicoSAT *);
+
+/*------------------------------------------------------------------------*/
+/* Add a literal of the next clause.  A zero terminates the clause.  The
+ * solver is incremental.  Adding a new literal will reset the previous
+ * assignment.   The return value is the original clause index to which
+ * this literal respectively the trailing zero belong starting at 0.
+ */
+int picosat_add (PicoSAT *, int lit);
+
+/* As the previous function, but allows to add a full clause at once with an
+ * at compiled time known size.  The list of argument literals has to be
+ * terminated with a zero literal.  Literals beyond the first zero literal
+ * are discarded.
+ */
+int picosat_add_arg (PicoSAT *, ...);
+
+/* As the previous function but with an at compile time unknown size.
+ */
+int picosat_add_lits (PicoSAT *, int * lits);
+
+/* Print the CNF to the given file in DIMACS format.
+ */
+void picosat_print (PicoSAT *, FILE *);
+
+/* You can add arbitrary many assumptions before the next 'picosat_sat'
+ * call.  This is similar to the using assumptions in MiniSAT, except that
+ * for PicoSAT you do not have to collect all your assumptions in a vector
+ * yourself.  In PicoSAT you can add one after the other, to be used in the 
+ * next call to 'picosat_sat'.
+ *
+ * These assumptions can be interpreted as adding unit clauses with those
+ * assumptions as literals.  However these assumption clauses are only valid
+ * for exactly the next call to 'picosat_sat', and will be removed
+ * afterwards, e.g. in following future calls to 'picosat_sat' after the
+ * next 'picosat_sat' call, unless they are assumed again trough
+ * 'picosat_assume'.
+ *
+ * More precisely, assumptions actually remain valid even after the next
+ * call to 'picosat_sat' has returned.  Valid means they remain 'assumed'
+ * internally until a call to 'picosat_add', 'picosat_assume', or a second
+ * 'picosat_sat', following the first 'picosat_sat'.  The reason for keeping
+ * them valid is to allow 'picosat_failed_assumption' to return correct
+ * values.  
+ *
+ * Example:
+ *
+ *   picosat_assume (1);        // assume unit clause '1 0'
+ *   picosat_assume (-2);       // additionally assume clause '-2 0'
+ *   res = picosat_sat (1000);  // assumes 1 and -2 to hold
+ *                              // 1000 decisions max.
+ *
+ *   if (res == PICOSAT_UNSATISFIABLE) 
+ *     {
+ *       if (picosat_failed_assumption (1))
+ *         // unit clause '1 0' was necessary to derive UNSAT
+ *
+ *       if (picosat_failed_assumption (-2))
+ *         // unit clause '-2 0' was necessary to derive UNSAT
+ *
+ *       // at least one but also both could be necessary
+ *
+ *       picosat_assume (17);  // previous assumptions are removed
+ *                             // now assume unit clause '17 0' for
+ *                             // the next call to 'picosat_sat'
+ *
+ *       // adding a new clause, actually the first literal of
+ *       // a clause would also make the assumptions used in the previous
+ *       // call to 'picosat_sat' invalid.
+ *
+ *       // The first two assumptions above are not assumed anymore.  Only
+ *       // the assumptions, since the last call to 'picosat_sat' returned
+ *       // are assumed, e.g. the unit clause '17 0'.
+ *
+ *       res = picosat_sat (-1);
+ *     }
+ *   else if (res == PICOSAT_SATISFIABLE)
+ *     {
+ *       // now the assignment is valid and we can call 'picosat_deref'
+ *
+ *       assert (picosat_deref (1) == 1));
+ *       assert (picosat_deref (-2) == 1));
+ *
+ *       val = picosat_deref (15);
+ *
+ *       // previous two assumptions are still valid
+ *
+ *       // would become invalid if 'picosat_add' or 'picosat_assume' is
+ *       // called here, but we immediately call 'picosat_sat'.  Now when
+ *       // entering 'picosat_sat' the solver knows that the previous call
+ *       // returned SAT and it can safely reset the previous assumptions
+ *
+ *       res = picosat_sat (-1);
+ *     }
+ *   else
+ *     {
+ *       assert (res == PICOSAT_UNKNOWN);
+ *
+ *       // assumptions valid, but assignment invalid
+ *       // except for top level assigned literals which
+ *       // necessarily need to have this value if the formula is SAT
+ *
+ *       // as above the solver nows that the previous call returned UNKWOWN
+ *       // and will before doing anything else reset assumptions
+ *
+ *       picosat_sat (-1);
+ *     }
+ */
+void picosat_assume (PicoSAT *, int lit);
+
+/*------------------------------------------------------------------------*/
+/* This is an experimental feature for handling 'all different constraints'
+ * (ADC).  Currently only one global ADC can be handled.  The bit-width of
+ * all the bit-vectors entered in this ADC (stored in 'all different
+ * objects' or ADOs) has to be identical.
+ *
+ * TODO: also handle top level assigned literals here.
+ */
+void picosat_add_ado_lit (PicoSAT *, int);
+
+/*------------------------------------------------------------------------*/
+/* Call the main SAT routine.  A negative decision limit sets no limit on
+ * the number of decisions.  The return values are as above, e.g.
+ * 'PICOSAT_UNSATISFIABLE', 'PICOSAT_SATISFIABLE', or 'PICOSAT_UNKNOWN'.
+ */
+int picosat_sat (PicoSAT *, int decision_limit);
+
+/* As alternative to a decision limit you can use the number of propagations
+ * as limit.  This is more linearly related to execution time. This has to
+ * be called after 'picosat_init' and before 'picosat_sat'.
+ */
+void picosat_set_propagation_limit (PicoSAT *, unsigned long long limit);
+
+/* Return last result of calling 'picosat_sat' or '0' if not called.
+ */
+int picosat_res (PicoSAT *);
+
+/* After 'picosat_sat' was called and returned 'PICOSAT_SATISFIABLE', then
+ * the satisfying assignment can be obtained by 'dereferencing' literals.
+ * The value of the literal is return as '1' for 'true',  '-1' for 'false'
+ * and '0' for an unknown value.
+ */
+int picosat_deref (PicoSAT *, int lit);
+
+/* Same as before but just returns true resp. false if the literals is
+ * forced to this assignment at the top level.  This function does not
+ * require that 'picosat_sat' was called and also does not internally reset
+ * incremental usage.
+ */
+int picosat_deref_toplevel (PicoSAT *, int lit);
+
+/* After 'picosat_sat' was called and returned 'PICOSAT_SATISFIABLE' a
+ * partial satisfying assignment can be obtained as well.  It satisfies all
+ * original clauses.  The value of the literal is return as '1' for 'true',
+ * '-1' for 'false' and '0' for an unknown value.  In order to make this
+ * work all original clauses have to be saved internally, which has to be
+ * enabled by 'picosat_save_original_clauses' right after initialization.
+ */
+int picosat_deref_partial (PicoSAT *, int lit);
+
+/* Returns non zero if the CNF is unsatisfiable because an empty clause was
+ * added or derived.
+ */
+int picosat_inconsistent  (PicoSAT *);
+
+/* Returns non zero if the literal is a failed assumption, which is defined
+ * as an assumption used to derive unsatisfiability.  This is as accurate as
+ * generating core literals, but still of course is an overapproximation of
+ * the set of assumptions really necessary.  The technique does not need
+ * clausal core generation nor tracing to be enabled and thus can be much
+ * more effective.  The function can only be called as long the current
+ * assumptions are valid.  See 'picosat_assume' for more details.
+ */
+int picosat_failed_assumption (PicoSAT *, int lit);
+
+/* Returns a zero terminated list of failed assumption in the last call to
+ * 'picosat_sat'.  The pointer is valid until the next call to
+ * 'picosat_sat' or 'picosat_failed_assumptions'.  It only makes sense if the
+ * last call to 'picosat_sat' returned 'PICOSAT_UNSATISFIABLE'.
+ */
+const int * picosat_failed_assumptions (PicoSAT *);
+
+/* Returns a zero terminated minimized list of failed assumption for the last
+ * call to 'picosat_sat'.  The pointer is valid until the next call to this
+ * function or 'picosat_sat' or 'picosat_mus_assumptions'.  It only makes sense
+ * if the last call to 'picosat_sat' returned 'PICOSAT_UNSATISFIABLE'.
+ *
+ * The call back function is called for all successful simplification
+ * attempts.  The first argument of the call back function is the state
+ * given as first argument to 'picosat_mus_assumptions'.  The second
+ * argument to the call back function is the new reduced list of failed
+ * assumptions.
+ *
+ * This function will call 'picosat_assume' and 'picosat_sat' internally but
+ * before returning reestablish a proper UNSAT state, e.g.
+ * 'picosat_failed_assumption' will work afterwards as expected.
+ *
+ * The last argument if non zero fixes assumptions.  In particular, if an
+ * assumption can not be removed it is permanently assigned true, otherwise
+ * if it turns out to be redundant it is permanently assumed to be false.
+ */
+const int * picosat_mus_assumptions (PicoSAT *, void *,
+                                     void(*)(void*,const int*),int);
+
+/* Compute one maximal subset of satisfiable assumptions.  You need to set
+ * the assumptions, call 'picosat_sat' and check for 'picosat_inconsistent',
+ * before calling this function.  The result is a zero terminated array of
+ * assumptions that consistently can be asserted at the same time.  Before
+ * returing the library 'reassumes' all assumptions.
+ *
+ * It could be beneficial to set the default phase of assumptions
+ * to true (positive).  This can speed up the computation.
+ */
+const int * picosat_maximal_satisfiable_subset_of_assumptions (PicoSAT *);
+
+/* This function assumes that you have set up all assumptions with
+ * 'picosat_assume'.  Then it calls 'picosat_sat' internally unless the
+ * formula is already inconsistent without assumptions, i.e.  it contains
+ * the empty clause.  After that it extracts a maximal satisfiable subset of
+ * assumptions.
+ *
+ * The result is a zero terminated maximal subset of consistent assumptions
+ * or a zero pointer if the formula contains the empty clause and thus no
+ * more maximal consistent subsets of assumptions can be extracted.  In the
+ * first case, before returning, a blocking clause is added, that rules out
+ * the result for the next call.
+ *
+ * NOTE: adding the blocking clause changes the CNF.
+ *
+ * So the following idiom
+ *
+ * const int * mss;
+ * picosat_assume (a1);
+ * picosat_assume (a2);
+ * picosat_assume (a3);
+ * picosat_assume (a4);
+ * while ((mss = picosat_next_maximal_satisfiable_subset_of_assumptions ()))
+ *   process_mss (mss);
+ *
+ * can be used to iterate over all maximal consistent subsets of
+ * the set of assumptions {a1,a2,a3,a4}.
+ *
+ * It could be beneficial to set the default phase of assumptions
+ * to true (positive).  This might speed up the computation.
+ */
+const int * 
+picosat_next_maximal_satisfiable_subset_of_assumptions (PicoSAT *);
+
+/* Similarly we can iterate over all minimal correcting assumption sets.
+ * See the CAMUS literature [M. Liffiton, K. Sakallah JAR 2008].
+ *
+ * The result contains each assumed literal only once, even if it
+ * was assumed multiple times (in contrast to the maximal consistent
+ * subset functions above).
+ *
+ * It could be beneficial to set the default phase of assumptions
+ * to true (positive).  This might speed up the computation.
+ */
+const int *
+picosat_next_minimal_correcting_subset_of_assumptions (PicoSAT *);
+
+/* Compute the union of all minmal correcting sets, which is called
+ * the 'high level union of all minimal unsatisfiable subset sets'
+ * or 'HUMUS' in our papers.
+ *
+ * It uses 'picosat_next_minimal_correcting_subset_of_assumptions' and
+ * the same notes and advices apply.  In particular, this implies that
+ * after calling the function once, the current CNF becomes inconsistent,
+ * and PicoSAT has to be reset.  So even this function internally uses
+ * PicoSAT incrementally, it can not be used incrementally itself at this
+ * point.
+ *
+ * The 'callback' can be used for progress logging and is called after
+ * each extracted minimal correcting set if non zero.  The 'nhumus'
+ * parameter of 'callback' denotes the number of assumptions found to be
+ * part of the HUMUS sofar.
+ */
+const int *
+picosat_humus (PicoSAT *,
+               void (*callback)(void * state, int nmcs, int nhumus),
+	       void * state);
+
+/*------------------------------------------------------------------------*/
+/* Assume that a previous call to 'picosat_sat' in incremental usage,
+ * returned 'SATISFIABLE'.  Then a couple of clauses and optionally new
+ * variables were added (a new variable is a variable that has an index
+ * larger then the maximum variable added so far).  The next call to
+ * 'picosat_sat' also returns 'SATISFIABLE'. If this function
+ * 'picosat_changed' returns '0', then the assignment to the old variables
+ * is guaranteed to not have changed.  Otherwise it might have changed.
+ * 
+ * The return value to this function is only valid until new clauses are
+ * added through 'picosat_add', an assumption is made through
+ * 'picosat_assume', or again 'picosat_sat' is called.  This is the same
+ * assumption as for 'picosat_deref'.
+ *
+ * TODO currently this function might also return a non zero value even if
+ * the old assignment did not change, because it only checks whether the
+ * assignment of at least one old variable was flipped at least once during
+ * the search.  In principle it should be possible to be exact in the other
+ * direction as well by using a counter of variables that have an odd number
+ * of flips.  But this is not implemented yet.
+ */
+int picosat_changed (PicoSAT *);
+
+/*------------------------------------------------------------------------*/
+/* The following six functions internally extract the variable and clausal
+ * core and thus require trace generation to be enabled with
+ * 'picosat_enable_trace_generation' right after calling 'picosat_init'.
+ *
+ * TODO: using these functions in incremental mode with failed assumptions
+ * has only been tested for 'picosat_corelit' thoroughly.  The others
+ * probably only work in non-incremental mode or without using
+ * 'picosat_assume'.
+ */
+
+/* This function determines whether the i'th added original clause is in the
+ * core.  The 'i' is the return value of 'picosat_add', which starts at zero
+ * and is incremented by one after a original clause is added (that is after
+ * 'picosat_add (0)').  For the index 'i' the following has to hold: 
+ *
+ *   0 <= i < picosat_added_original_clauses ()
+ */
+int picosat_coreclause (PicoSAT *, int i);
+
+/* This function gives access to the variable core, which is made up of the
+ * variables that were resolved in deriving the empty clause.
+ */
+int picosat_corelit (PicoSAT *, int lit);
+
+/* Write the clauses that were used in deriving the empty clause to a file
+ * in DIMACS format.
+ */
+void picosat_write_clausal_core (PicoSAT *, FILE * core_file);
+
+/* Write a proof trace in TraceCheck format to a file.
+ */
+void picosat_write_compact_trace (PicoSAT *, FILE * trace_file);
+void picosat_write_extended_trace (PicoSAT *, FILE * trace_file);
+
+/* Write a RUP trace to a file.  This trace file contains only the learned
+ * core clauses while this is not necessarily the case for the RUP file
+ * obtained with 'picosat_set_incremental_rup_file'.
+ */
+void picosat_write_rup_trace (PicoSAT *, FILE * trace_file);
+
+/*------------------------------------------------------------------------*/
+/* Keeping the proof trace around is not necessary if an over-approximation
+ * of the core is enough.  A literal is 'used' if it was involved in a
+ * resolution to derive a learned clause.  The core literals are necessarily
+ * a subset of the 'used' literals.
+ */
+
+int picosat_usedlit (PicoSAT *, int lit);
+/*------------------------------------------------------------------------*/
+#endif
diff --git a/test/picosat-965/version.c b/test/picosat-965/version.c
new file mode 100644
index 00000000..71c322bd
--- /dev/null
+++ b/test/picosat-965/version.c
@@ -0,0 +1,14 @@
+#include "config.h"
+
+const char *
+picosat_version (void)
+{
+  return PICOSAT_VERSION;
+}
+
+const char *
+picosat_config (void)
+{
+  return PICOSAT_CC " " PICOSAT_CFLAGS;
+}
+