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Diffstat (limited to 'test/monniaux/glpk-4.65/src/api/asnhall.c')
| -rw-r--r-- | test/monniaux/glpk-4.65/src/api/asnhall.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/test/monniaux/glpk-4.65/src/api/asnhall.c b/test/monniaux/glpk-4.65/src/api/asnhall.c new file mode 100644 index 00000000..d7112a10 --- /dev/null +++ b/test/monniaux/glpk-4.65/src/api/asnhall.c @@ -0,0 +1,163 @@ +/* asnhall.c (find bipartite matching of maximum cardinality) */ + +/*********************************************************************** +* This code is part of GLPK (GNU Linear Programming Kit). +* +* Copyright (C) 2009-2016 Andrew Makhorin, Department for Applied +* Informatics, Moscow Aviation Institute, Moscow, Russia. All rights +* reserved. E-mail: <mao@gnu.org>. +* +* GLPK is free software: you can redistribute it and/or modify it +* under the terms of the GNU General Public License as published by +* the Free Software Foundation, either version 3 of the License, or +* (at your option) any later version. +* +* GLPK is distributed in the hope that it will be useful, but WITHOUT +* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public +* License for more details. +* +* You should have received a copy of the GNU General Public License +* along with GLPK. If not, see <http://www.gnu.org/licenses/>. +***********************************************************************/ + +#include "env.h" +#include "glpk.h" +#include "mc21a.h" + +/*********************************************************************** +* NAME +* +* glp_asnprob_hall - find bipartite matching of maximum cardinality +* +* SYNOPSIS +* +* int glp_asnprob_hall(glp_graph *G, int v_set, int a_x); +* +* DESCRIPTION +* +* The routine glp_asnprob_hall finds a matching of maximal cardinality +* in the specified bipartite graph G. It uses a version of the Fortran +* routine MC21A developed by I.S.Duff [1], which implements Hall's +* algorithm [2]. +* +* RETURNS +* +* The routine glp_asnprob_hall returns the cardinality of the matching +* found. However, if the specified graph is incorrect (as detected by +* the routine glp_check_asnprob), the routine returns negative value. +* +* REFERENCES +* +* 1. I.S.Duff, Algorithm 575: Permutations for zero-free diagonal, ACM +* Trans. on Math. Softw. 7 (1981), 387-390. +* +* 2. M.Hall, "An Algorithm for distinct representatives," Amer. Math. +* Monthly 63 (1956), 716-717. */ + +int glp_asnprob_hall(glp_graph *G, int v_set, int a_x) +{ glp_vertex *v; + glp_arc *a; + int card, i, k, loc, n, n1, n2, xij; + int *num, *icn, *ip, *lenr, *iperm, *pr, *arp, *cv, *out; + if (v_set >= 0 && v_set > G->v_size - (int)sizeof(int)) + xerror("glp_asnprob_hall: v_set = %d; invalid offset\n", + v_set); + if (a_x >= 0 && a_x > G->a_size - (int)sizeof(int)) + xerror("glp_asnprob_hall: a_x = %d; invalid offset\n", a_x); + if (glp_check_asnprob(G, v_set)) + return -1; + /* determine the number of vertices in sets R and S and renumber + vertices in S which correspond to columns of the matrix; skip + all isolated vertices */ + num = xcalloc(1+G->nv, sizeof(int)); + n1 = n2 = 0; + for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + if (v->in == NULL && v->out != NULL) + n1++, num[i] = 0; /* vertex in R */ + else if (v->in != NULL && v->out == NULL) + n2++, num[i] = n2; /* vertex in S */ + else + { xassert(v->in == NULL && v->out == NULL); + num[i] = -1; /* isolated vertex */ + } + } + /* the matrix must be square, thus, if it has more columns than + rows, extra rows will be just empty, and vice versa */ + n = (n1 >= n2 ? n1 : n2); + /* allocate working arrays */ + icn = xcalloc(1+G->na, sizeof(int)); + ip = xcalloc(1+n, sizeof(int)); + lenr = xcalloc(1+n, sizeof(int)); + iperm = xcalloc(1+n, sizeof(int)); + pr = xcalloc(1+n, sizeof(int)); + arp = xcalloc(1+n, sizeof(int)); + cv = xcalloc(1+n, sizeof(int)); + out = xcalloc(1+n, sizeof(int)); + /* build the adjacency matrix of the bipartite graph in row-wise + format (rows are vertices in R, columns are vertices in S) */ + k = 0, loc = 1; + for (i = 1; i <= G->nv; i++) + { if (num[i] != 0) continue; + /* vertex i in R */ + ip[++k] = loc; + v = G->v[i]; + for (a = v->out; a != NULL; a = a->t_next) + { xassert(num[a->head->i] != 0); + icn[loc++] = num[a->head->i]; + } + lenr[k] = loc - ip[k]; + } + xassert(loc-1 == G->na); + /* make all extra rows empty (all extra columns are empty due to + the row-wise format used) */ + for (k++; k <= n; k++) + ip[k] = loc, lenr[k] = 0; + /* find a row permutation that maximizes the number of non-zeros + on the main diagonal */ + card = mc21a(n, icn, ip, lenr, iperm, pr, arp, cv, out); +#if 1 /* 18/II-2010 */ + /* FIXED: if card = n, arp remains clobbered on exit */ + for (i = 1; i <= n; i++) + arp[i] = 0; + for (i = 1; i <= card; i++) + { k = iperm[i]; + xassert(1 <= k && k <= n); + xassert(arp[k] == 0); + arp[k] = i; + } +#endif + /* store solution, if necessary */ + if (a_x < 0) goto skip; + k = 0; + for (i = 1; i <= G->nv; i++) + { if (num[i] != 0) continue; + /* vertex i in R */ + k++; + v = G->v[i]; + for (a = v->out; a != NULL; a = a->t_next) + { /* arp[k] is the number of matched column or zero */ + if (arp[k] == num[a->head->i]) + { xassert(arp[k] != 0); + xij = 1; + } + else + xij = 0; + memcpy((char *)a->data + a_x, &xij, sizeof(int)); + } + } +skip: /* free working arrays */ + xfree(num); + xfree(icn); + xfree(ip); + xfree(lenr); + xfree(iperm); + xfree(pr); + xfree(arp); + xfree(cv); + xfree(out); + return card; +} + +/* eof */ |