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diff --git a/test/ccured_olden/bh/Readme b/test/ccured_olden/bh/Readme new file mode 100644 index 00000000..5034f519 --- /dev/null +++ b/test/ccured_olden/bh/Readme @@ -0,0 +1,62 @@ +README README README README README README README README README README + + 22 June 1993 + + This is the fourth release of the hierarchical N-body program. The +algorithm used to compute gravitational forces has asymptotic complexity of +O(N log N). This is achieved by building a tree structure to represent the +mass distribution and estimating forces by a partial recursive descent of this +tree. See "A Hierarchical O(N log N) Force Calculation Algorithm", by Joshua +Barnes and Piet Hut, Nature, 324, 446, and "Error Analysis of a Tree Code", by +Joshua Barnes and Piet Hut, Astrophysical Journal Supplement, 70, 389, for +more information. + + The code has been rewritten in ANSI C for greater portability. Prototypes +have been provided for all functions. Several functions associated with tree +construction have been simplified; the resulting code should be easier to +mantain. Force calculation has been made more accurate by incorporating a new +opening-angle criterion, and faster by adding additional pointers to the tree +structure. Quadrupole corrections for body-cell interactions are now included +as a run-time option; see "Performance Characteristics of Tree Codes", by Lars +Hernquist, Astrophysical Journal Supplement, 64, 715. + + The source files for the tree code have been bundled together for ease of +distribution. On a UNIX system, you can split this file simply by invoking +the Bourne shell on it (use the sh command). On other systems, you may have +to edit this file and split it up by hand; note that file X is delimited by +lines containing the message End of X. Once you have split this file, you can +compile it by running make on a UNIX system. On other systems, you are on +your own; take a look at the Makefile for hints. Running the program with the +default input parameters (type a <CR> to all prompts) will start a short +calculation with a few particles to test things out. + + These sources include a few files which you may find generally useful: +"stdinc.h", a standard include file with common definitions, "vectmath.h", a +set of macros for elementary vector and matrix operations, "real.h", a set of +definitions for floating-point code, "getparam.c", a simple, standardized user +interface, and "util.c", some miscellaneous utilities. These are part of a +larger collection of software for numerical experiments with gravitating +systems. + + NO WARRANTY is offered on the software supplied here -- use it at your own +risk. NO RESTRICTIONS are imposed on use and distribution of the code -- you +are free to use this software for any application, modify it in any way, use +pieces in other programs, and give it away to anyone else. You are encouraged +to extend these rights to others who receive this software from you, following +the philosophy and intentions of the Free Software Foundation. + + You are asked to include a brief acknowledgement in any scientific papers +you write using this code; I would appreciate receiving preprints or reprints +of such papers. I would also appreciate receiving reports of bugs and/or +problems encountered in porting this code to other machines. + + Have fun and stay in touch. + + Joshua E. Barnes barnes@zeno.ifa.hawaii.edu + + Institute for Astronomy (808) 956-8138 + University of Hawaii + 2680 Woodlawn Drive + Honolulu, Hawaii 96822 + +README README README README README README README README README README |