diff options
Diffstat (limited to 'test/monniaux/glpk-4.65/src/api/maxffalg.c')
| -rw-r--r-- | test/monniaux/glpk-4.65/src/api/maxffalg.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/test/monniaux/glpk-4.65/src/api/maxffalg.c b/test/monniaux/glpk-4.65/src/api/maxffalg.c new file mode 100644 index 00000000..0f3f9b04 --- /dev/null +++ b/test/monniaux/glpk-4.65/src/api/maxffalg.c @@ -0,0 +1,130 @@ +/* maxffalg.c (find maximal flow with Ford-Fulkerson algorithm) */ + +/*********************************************************************** +* 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 "ffalg.h" +#include "glpk.h" + +int glp_maxflow_ffalg(glp_graph *G, int s, int t, int a_cap, + double *sol, int a_x, int v_cut) +{ /* find maximal flow with Ford-Fulkerson algorithm */ + glp_vertex *v; + glp_arc *a; + int nv, na, i, k, flag, *tail, *head, *cap, *x, ret; + char *cut; + double temp; + if (!(1 <= s && s <= G->nv)) + xerror("glp_maxflow_ffalg: s = %d; source node number out of r" + "ange\n", s); + if (!(1 <= t && t <= G->nv)) + xerror("glp_maxflow_ffalg: t = %d: sink node number out of ran" + "ge\n", t); + if (s == t) + xerror("glp_maxflow_ffalg: s = t = %d; source and sink nodes m" + "ust be distinct\n", s); + if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double)) + xerror("glp_maxflow_ffalg: a_cap = %d; invalid offset\n", + a_cap); + if (v_cut >= 0 && v_cut > G->v_size - (int)sizeof(int)) + xerror("glp_maxflow_ffalg: v_cut = %d; invalid offset\n", + v_cut); + /* allocate working arrays */ + nv = G->nv; + na = G->na; + tail = xcalloc(1+na, sizeof(int)); + head = xcalloc(1+na, sizeof(int)); + cap = xcalloc(1+na, sizeof(int)); + x = xcalloc(1+na, sizeof(int)); + if (v_cut < 0) + cut = NULL; + else + cut = xcalloc(1+nv, sizeof(char)); + /* copy the flow network */ + k = 0; + for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + for (a = v->out; a != NULL; a = a->t_next) + { k++; + tail[k] = a->tail->i; + head[k] = a->head->i; + if (tail[k] == head[k]) + { ret = GLP_EDATA; + goto done; + } + if (a_cap >= 0) + memcpy(&temp, (char *)a->data + a_cap, sizeof(double)); + else + temp = 1.0; + if (!(0.0 <= temp && temp <= (double)INT_MAX && + temp == floor(temp))) + { ret = GLP_EDATA; + goto done; + } + cap[k] = (int)temp; + } + } + xassert(k == na); + /* find maximal flow in the flow network */ + ffalg(nv, na, tail, head, s, t, cap, x, cut); + ret = 0; + /* store solution components */ + /* (objective function = total flow through the network) */ + if (sol != NULL) + { temp = 0.0; + for (k = 1; k <= na; k++) + { if (tail[k] == s) + temp += (double)x[k]; + else if (head[k] == s) + temp -= (double)x[k]; + } + *sol = temp; + } + /* (arc flows) */ + if (a_x >= 0) + { k = 0; + for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + for (a = v->out; a != NULL; a = a->t_next) + { temp = (double)x[++k]; + memcpy((char *)a->data + a_x, &temp, sizeof(double)); + } + } + } + /* (node flags) */ + if (v_cut >= 0) + { for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + flag = cut[i]; + memcpy((char *)v->data + v_cut, &flag, sizeof(int)); + } + } +done: /* free working arrays */ + xfree(tail); + xfree(head); + xfree(cap); + xfree(x); + if (cut != NULL) xfree(cut); + return ret; +} + +/* eof */ |