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author | Pasha <pasha@member.fsf.org> | 2023-01-27 00:54:07 +0000 |
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committer | Pasha <pasha@member.fsf.org> | 2023-01-27 00:54:07 +0000 |
commit | ef800d4ffafdbde7d7a172ad73bd984b1695c138 (patch) | |
tree | 920cc189130f1e98f252283fce94851443641a6d /glpk-5.0/src/api/mcfokalg.c | |
parent | ec4ae3c2b5cb0e83fb667f14f832ea94f68ef075 (diff) | |
download | oneapi-ef800d4ffafdbde7d7a172ad73bd984b1695c138.tar.gz oneapi-ef800d4ffafdbde7d7a172ad73bd984b1695c138.tar.bz2 |
Diffstat (limited to 'glpk-5.0/src/api/mcfokalg.c')
-rw-r--r-- | glpk-5.0/src/api/mcfokalg.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/glpk-5.0/src/api/mcfokalg.c b/glpk-5.0/src/api/mcfokalg.c new file mode 100644 index 0000000..c2d2794 --- /dev/null +++ b/glpk-5.0/src/api/mcfokalg.c @@ -0,0 +1,219 @@ +/* mcfokalg.c (find minimum-cost flow with out-of-kilter algorithm) */ + +/*********************************************************************** +* This code is part of GLPK (GNU Linear Programming Kit). +* Copyright (C) 2009-2016 Free Software Foundation, Inc. +* Written by Andrew Makhorin <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 "okalg.h" + +int glp_mincost_okalg(glp_graph *G, int v_rhs, int a_low, int a_cap, + int a_cost, double *sol, int a_x, int v_pi) +{ /* find minimum-cost flow with out-of-kilter algorithm */ + glp_vertex *v; + glp_arc *a; + int nv, na, i, k, s, t, *tail, *head, *low, *cap, *cost, *x, *pi, + ret; + double sum, temp; + if (v_rhs >= 0 && v_rhs > G->v_size - (int)sizeof(double)) + xerror("glp_mincost_okalg: v_rhs = %d; invalid offset\n", + v_rhs); + if (a_low >= 0 && a_low > G->a_size - (int)sizeof(double)) + xerror("glp_mincost_okalg: a_low = %d; invalid offset\n", + a_low); + if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double)) + xerror("glp_mincost_okalg: a_cap = %d; invalid offset\n", + a_cap); + if (a_cost >= 0 && a_cost > G->a_size - (int)sizeof(double)) + xerror("glp_mincost_okalg: a_cost = %d; invalid offset\n", + a_cost); + if (a_x >= 0 && a_x > G->a_size - (int)sizeof(double)) + xerror("glp_mincost_okalg: a_x = %d; invalid offset\n", a_x); + if (v_pi >= 0 && v_pi > G->v_size - (int)sizeof(double)) + xerror("glp_mincost_okalg: v_pi = %d; invalid offset\n", v_pi); + /* s is artificial source node */ + s = G->nv + 1; + /* t is artificial sink node */ + t = s + 1; + /* nv is the total number of nodes in the resulting network */ + nv = t; + /* na is the total number of arcs in the resulting network */ + na = G->na + 1; + for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + if (v_rhs >= 0) + memcpy(&temp, (char *)v->data + v_rhs, sizeof(double)); + else + temp = 0.0; + if (temp != 0.0) na++; + } + /* allocate working arrays */ + tail = xcalloc(1+na, sizeof(int)); + head = xcalloc(1+na, sizeof(int)); + low = xcalloc(1+na, sizeof(int)); + cap = xcalloc(1+na, sizeof(int)); + cost = xcalloc(1+na, sizeof(int)); + x = xcalloc(1+na, sizeof(int)); + pi = xcalloc(1+nv, sizeof(int)); + /* construct the resulting network */ + k = 0; + /* (original arcs) */ + 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_low >= 0) + memcpy(&temp, (char *)a->data + a_low, sizeof(double)); + else + temp = 0.0; + if (!(0.0 <= temp && temp <= (double)INT_MAX && + temp == floor(temp))) + { ret = GLP_EDATA; + goto done; + } + low[k] = (int)temp; + if (a_cap >= 0) + memcpy(&temp, (char *)a->data + a_cap, sizeof(double)); + else + temp = 1.0; + if (!((double)low[k] <= temp && temp <= (double)INT_MAX && + temp == floor(temp))) + { ret = GLP_EDATA; + goto done; + } + cap[k] = (int)temp; + if (a_cost >= 0) + memcpy(&temp, (char *)a->data + a_cost, sizeof(double)); + else + temp = 0.0; + if (!(fabs(temp) <= (double)INT_MAX && temp == floor(temp))) + { ret = GLP_EDATA; + goto done; + } + cost[k] = (int)temp; + } + } + /* (artificial arcs) */ + sum = 0.0; + for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + if (v_rhs >= 0) + memcpy(&temp, (char *)v->data + v_rhs, sizeof(double)); + else + temp = 0.0; + if (!(fabs(temp) <= (double)INT_MAX && temp == floor(temp))) + { ret = GLP_EDATA; + goto done; + } + if (temp > 0.0) + { /* artificial arc from s to original source i */ + k++; + tail[k] = s; + head[k] = i; + low[k] = cap[k] = (int)(+temp); /* supply */ + cost[k] = 0; + sum += (double)temp; + } + else if (temp < 0.0) + { /* artificial arc from original sink i to t */ + k++; + tail[k] = i; + head[k] = t; + low[k] = cap[k] = (int)(-temp); /* demand */ + cost[k] = 0; + } + } + /* (feedback arc from t to s) */ + k++; + xassert(k == na); + tail[k] = t; + head[k] = s; + if (sum > (double)INT_MAX) + { ret = GLP_EDATA; + goto done; + } + low[k] = cap[k] = (int)sum; /* total supply/demand */ + cost[k] = 0; + /* find minimal-cost circulation in the resulting network */ + ret = okalg(nv, na, tail, head, low, cap, cost, x, pi); + switch (ret) + { case 0: + /* optimal circulation found */ + ret = 0; + break; + case 1: + /* no feasible circulation exists */ + ret = GLP_ENOPFS; + break; + case 2: + /* integer overflow occured */ + ret = GLP_ERANGE; + goto done; + case 3: + /* optimality test failed (logic error) */ + ret = GLP_EFAIL; + goto done; + default: + xassert(ret != ret); + } + /* store solution components */ + /* (objective function = the total cost) */ + if (sol != NULL) + { temp = 0.0; + for (k = 1; k <= na; k++) + temp += (double)cost[k] * (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 potentials = Lagrange multipliers) */ + if (v_pi >= 0) + { for (i = 1; i <= G->nv; i++) + { v = G->v[i]; + temp = - (double)pi[i]; + memcpy((char *)v->data + v_pi, &temp, sizeof(double)); + } + } +done: /* free working arrays */ + xfree(tail); + xfree(head); + xfree(low); + xfree(cap); + xfree(cost); + xfree(x); + xfree(pi); + return ret; +} + +/* eof */ |