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tempest/resources/3rdparty/glpk-4.53/src/glpapi09.c

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/* glpapi09.c (mixed integer programming routines) */
/***********************************************************************
* This code is part of GLPK (GNU Linear Programming Kit).
*
* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
* 2009, 2010, 2011, 2013 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 "draft.h"
#include "env.h"
#include "glpios.h"
#include "glpnpp.h"
/***********************************************************************
* NAME
*
* glp_set_col_kind - set (change) column kind
*
* SYNOPSIS
*
* void glp_set_col_kind(glp_prob *mip, int j, int kind);
*
* DESCRIPTION
*
* The routine glp_set_col_kind sets (changes) the kind of j-th column
* (structural variable) as specified by the parameter kind:
*
* GLP_CV - continuous variable;
* GLP_IV - integer variable;
* GLP_BV - binary variable. */
void glp_set_col_kind(glp_prob *mip, int j, int kind)
{ GLPCOL *col;
if (!(1 <= j && j <= mip->n))
xerror("glp_set_col_kind: j = %d; column number out of range\n"
, j);
col = mip->col[j];
switch (kind)
{ case GLP_CV:
col->kind = GLP_CV;
break;
case GLP_IV:
col->kind = GLP_IV;
break;
case GLP_BV:
col->kind = GLP_IV;
if (!(col->type == GLP_DB && col->lb == 0.0 && col->ub ==
1.0)) glp_set_col_bnds(mip, j, GLP_DB, 0.0, 1.0);
break;
default:
xerror("glp_set_col_kind: j = %d; kind = %d; invalid column"
" kind\n", j, kind);
}
return;
}
/***********************************************************************
* NAME
*
* glp_get_col_kind - retrieve column kind
*
* SYNOPSIS
*
* int glp_get_col_kind(glp_prob *mip, int j);
*
* RETURNS
*
* The routine glp_get_col_kind returns the kind of j-th column, i.e.
* the kind of corresponding structural variable, as follows:
*
* GLP_CV - continuous variable;
* GLP_IV - integer variable;
* GLP_BV - binary variable */
int glp_get_col_kind(glp_prob *mip, int j)
{ GLPCOL *col;
int kind;
if (!(1 <= j && j <= mip->n))
xerror("glp_get_col_kind: j = %d; column number out of range\n"
, j);
col = mip->col[j];
kind = col->kind;
switch (kind)
{ case GLP_CV:
break;
case GLP_IV:
if (col->type == GLP_DB && col->lb == 0.0 && col->ub == 1.0)
kind = GLP_BV;
break;
default:
xassert(kind != kind);
}
return kind;
}
/***********************************************************************
* NAME
*
* glp_get_num_int - retrieve number of integer columns
*
* SYNOPSIS
*
* int glp_get_num_int(glp_prob *mip);
*
* RETURNS
*
* The routine glp_get_num_int returns the current number of columns,
* which are marked as integer. */
int glp_get_num_int(glp_prob *mip)
{ GLPCOL *col;
int j, count = 0;
for (j = 1; j <= mip->n; j++)
{ col = mip->col[j];
if (col->kind == GLP_IV) count++;
}
return count;
}
/***********************************************************************
* NAME
*
* glp_get_num_bin - retrieve number of binary columns
*
* SYNOPSIS
*
* int glp_get_num_bin(glp_prob *mip);
*
* RETURNS
*
* The routine glp_get_num_bin returns the current number of columns,
* which are marked as binary. */
int glp_get_num_bin(glp_prob *mip)
{ GLPCOL *col;
int j, count = 0;
for (j = 1; j <= mip->n; j++)
{ col = mip->col[j];
if (col->kind == GLP_IV && col->type == GLP_DB && col->lb ==
0.0 && col->ub == 1.0) count++;
}
return count;
}
/***********************************************************************
* NAME
*
* glp_intopt - solve MIP problem with the branch-and-bound method
*
* SYNOPSIS
*
* int glp_intopt(glp_prob *P, const glp_iocp *parm);
*
* DESCRIPTION
*
* The routine glp_intopt is a driver to the MIP solver based on the
* branch-and-bound method.
*
* On entry the problem object should contain optimal solution to LP
* relaxation (which can be obtained with the routine glp_simplex).
*
* The MIP solver has a set of control parameters. Values of the control
* parameters can be passed in a structure glp_iocp, which the parameter
* parm points to.
*
* The parameter parm can be specified as NULL, in which case the MIP
* solver uses default settings.
*
* RETURNS
*
* 0 The MIP problem instance has been successfully solved. This code
* does not necessarily mean that the solver has found optimal
* solution. It only means that the solution process was successful.
*
* GLP_EBOUND
* Unable to start the search, because some double-bounded variables
* have incorrect bounds or some integer variables have non-integer
* (fractional) bounds.
*
* GLP_EROOT
* Unable to start the search, because optimal basis for initial LP
* relaxation is not provided.
*
* GLP_EFAIL
* The search was prematurely terminated due to the solver failure.
*
* GLP_EMIPGAP
* The search was prematurely terminated, because the relative mip
* gap tolerance has been reached.
*
* GLP_ETMLIM
* The search was prematurely terminated, because the time limit has
* been exceeded.
*
* GLP_ENOPFS
* The MIP problem instance has no primal feasible solution (only if
* the MIP presolver is used).
*
* GLP_ENODFS
* LP relaxation of the MIP problem instance has no dual feasible
* solution (only if the MIP presolver is used).
*
* GLP_ESTOP
* The search was prematurely terminated by application. */
#if 0 /* 11/VII-2013 */
static int solve_mip(glp_prob *P, const glp_iocp *parm)
#else
static int solve_mip(glp_prob *P, const glp_iocp *parm,
glp_prob *P0 /* problem passed to glp_intopt */,
NPP *npp /* preprocessor workspace or NULL */)
#endif
{ /* solve MIP directly without using the preprocessor */
glp_tree *T;
int ret;
/* optimal basis to LP relaxation must be provided */
if (glp_get_status(P) != GLP_OPT)
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: optimal basis to initial LP relaxation"
" not provided\n");
ret = GLP_EROOT;
goto done;
}
/* it seems all is ok */
if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("Integer optimization begins...\n");
/* create the branch-and-bound tree */
T = ios_create_tree(P, parm);
#if 1 /* 11/VII-2013 */
T->P = P0;
T->npp = npp;
#endif
/* solve the problem instance */
ret = ios_driver(T);
/* delete the branch-and-bound tree */
ios_delete_tree(T);
/* analyze exit code reported by the mip driver */
if (ret == 0)
{ if (P->mip_stat == GLP_FEAS)
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("INTEGER OPTIMAL SOLUTION FOUND\n");
P->mip_stat = GLP_OPT;
}
else
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("PROBLEM HAS NO INTEGER FEASIBLE SOLUTION\n");
P->mip_stat = GLP_NOFEAS;
}
}
else if (ret == GLP_EMIPGAP)
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("RELATIVE MIP GAP TOLERANCE REACHED; SEARCH TERMINA"
"TED\n");
}
else if (ret == GLP_ETMLIM)
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("TIME LIMIT EXCEEDED; SEARCH TERMINATED\n");
}
else if (ret == GLP_EFAIL)
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: cannot solve current LP relaxation\n");
}
else if (ret == GLP_ESTOP)
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("SEARCH TERMINATED BY APPLICATION\n");
}
else
xassert(ret != ret);
done: return ret;
}
static int preprocess_and_solve_mip(glp_prob *P, const glp_iocp *parm)
{ /* solve MIP using the preprocessor */
ENV *env = get_env_ptr();
int term_out = env->term_out;
NPP *npp;
glp_prob *mip = NULL;
glp_bfcp bfcp;
glp_smcp smcp;
int ret;
if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("Preprocessing...\n");
/* create preprocessor workspace */
npp = npp_create_wksp();
/* load original problem into the preprocessor workspace */
npp_load_prob(npp, P, GLP_OFF, GLP_MIP, GLP_OFF);
/* process MIP prior to applying the branch-and-bound method */
if (!term_out || parm->msg_lev < GLP_MSG_ALL)
env->term_out = GLP_OFF;
else
env->term_out = GLP_ON;
ret = npp_integer(npp, parm);
env->term_out = term_out;
if (ret == 0)
;
else if (ret == GLP_ENOPFS)
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("PROBLEM HAS NO PRIMAL FEASIBLE SOLUTION\n");
}
else if (ret == GLP_ENODFS)
{ if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("LP RELAXATION HAS NO DUAL FEASIBLE SOLUTION\n");
}
else
xassert(ret != ret);
if (ret != 0) goto done;
/* build transformed MIP */
mip = glp_create_prob();
npp_build_prob(npp, mip);
/* if the transformed MIP is empty, it has empty solution, which
is optimal */
if (mip->m == 0 && mip->n == 0)
{ mip->mip_stat = GLP_OPT;
mip->mip_obj = mip->c0;
if (parm->msg_lev >= GLP_MSG_ALL)
{ xprintf("Objective value = %17.9e\n", mip->mip_obj);
xprintf("INTEGER OPTIMAL SOLUTION FOUND BY MIP PREPROCESSOR"
"\n");
}
goto post;
}
/* display some statistics */
if (parm->msg_lev >= GLP_MSG_ALL)
{ int ni = glp_get_num_int(mip);
int nb = glp_get_num_bin(mip);
char s[50];
xprintf("%d row%s, %d column%s, %d non-zero%s\n",
mip->m, mip->m == 1 ? "" : "s", mip->n, mip->n == 1 ? "" :
"s", mip->nnz, mip->nnz == 1 ? "" : "s");
if (nb == 0)
strcpy(s, "none of");
else if (ni == 1 && nb == 1)
strcpy(s, "");
else if (nb == 1)
strcpy(s, "one of");
else if (nb == ni)
strcpy(s, "all of");
else
sprintf(s, "%d of", nb);
xprintf("%d integer variable%s, %s which %s binary\n",
ni, ni == 1 ? "" : "s", s, nb == 1 ? "is" : "are");
}
/* inherit basis factorization control parameters */
glp_get_bfcp(P, &bfcp);
glp_set_bfcp(mip, &bfcp);
/* scale the transformed problem */
if (!term_out || parm->msg_lev < GLP_MSG_ALL)
env->term_out = GLP_OFF;
else
env->term_out = GLP_ON;
glp_scale_prob(mip,
GLP_SF_GM | GLP_SF_EQ | GLP_SF_2N | GLP_SF_SKIP);
env->term_out = term_out;
/* build advanced initial basis */
if (!term_out || parm->msg_lev < GLP_MSG_ALL)
env->term_out = GLP_OFF;
else
env->term_out = GLP_ON;
glp_adv_basis(mip, 0);
env->term_out = term_out;
/* solve initial LP relaxation */
if (parm->msg_lev >= GLP_MSG_ALL)
xprintf("Solving LP relaxation...\n");
glp_init_smcp(&smcp);
smcp.msg_lev = parm->msg_lev;
mip->it_cnt = P->it_cnt;
ret = glp_simplex(mip, &smcp);
P->it_cnt = mip->it_cnt;
if (ret != 0)
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: cannot solve LP relaxation\n");
ret = GLP_EFAIL;
goto done;
}
/* check status of the basic solution */
ret = glp_get_status(mip);
if (ret == GLP_OPT)
ret = 0;
else if (ret == GLP_NOFEAS)
ret = GLP_ENOPFS;
else if (ret == GLP_UNBND)
ret = GLP_ENODFS;
else
xassert(ret != ret);
if (ret != 0) goto done;
/* solve the transformed MIP */
mip->it_cnt = P->it_cnt;
#if 0 /* 11/VII-2013 */
ret = solve_mip(mip, parm);
#else
if (parm->use_sol)
{ mip->mip_stat = P->mip_stat;
mip->mip_obj = P->mip_obj;
}
ret = solve_mip(mip, parm, P, npp);
#endif
P->it_cnt = mip->it_cnt;
/* only integer feasible solution can be postprocessed */
if (!(mip->mip_stat == GLP_OPT || mip->mip_stat == GLP_FEAS))
{ P->mip_stat = mip->mip_stat;
goto done;
}
/* postprocess solution from the transformed MIP */
post: npp_postprocess(npp, mip);
/* the transformed MIP is no longer needed */
glp_delete_prob(mip), mip = NULL;
/* store solution to the original problem */
npp_unload_sol(npp, P);
done: /* delete the transformed MIP, if it exists */
if (mip != NULL) glp_delete_prob(mip);
/* delete preprocessor workspace */
npp_delete_wksp(npp);
return ret;
}
#ifndef HAVE_ALIEN_SOLVER /* 28/V-2010 */
int _glp_intopt1(glp_prob *P, const glp_iocp *parm)
{ xassert(P == P);
xassert(parm == parm);
xprintf("glp_intopt: no alien solver is available\n");
return GLP_EFAIL;
}
#endif
int glp_intopt(glp_prob *P, const glp_iocp *parm)
{ /* solve MIP problem with the branch-and-bound method */
glp_iocp _parm;
int i, j, ret;
/* check problem object */
if (P == NULL || P->magic != GLP_PROB_MAGIC)
xerror("glp_intopt: P = %p; invalid problem object\n", P);
if (P->tree != NULL)
xerror("glp_intopt: operation not allowed\n");
/* check control parameters */
if (parm == NULL)
parm = &_parm, glp_init_iocp((glp_iocp *)parm);
if (!(parm->msg_lev == GLP_MSG_OFF ||
parm->msg_lev == GLP_MSG_ERR ||
parm->msg_lev == GLP_MSG_ON ||
parm->msg_lev == GLP_MSG_ALL ||
parm->msg_lev == GLP_MSG_DBG))
xerror("glp_intopt: msg_lev = %d; invalid parameter\n",
parm->msg_lev);
if (!(parm->br_tech == GLP_BR_FFV ||
parm->br_tech == GLP_BR_LFV ||
parm->br_tech == GLP_BR_MFV ||
parm->br_tech == GLP_BR_DTH ||
parm->br_tech == GLP_BR_PCH))
xerror("glp_intopt: br_tech = %d; invalid parameter\n",
parm->br_tech);
if (!(parm->bt_tech == GLP_BT_DFS ||
parm->bt_tech == GLP_BT_BFS ||
parm->bt_tech == GLP_BT_BLB ||
parm->bt_tech == GLP_BT_BPH))
xerror("glp_intopt: bt_tech = %d; invalid parameter\n",
parm->bt_tech);
if (!(0.0 < parm->tol_int && parm->tol_int < 1.0))
xerror("glp_intopt: tol_int = %g; invalid parameter\n",
parm->tol_int);
if (!(0.0 < parm->tol_obj && parm->tol_obj < 1.0))
xerror("glp_intopt: tol_obj = %g; invalid parameter\n",
parm->tol_obj);
if (parm->tm_lim < 0)
xerror("glp_intopt: tm_lim = %d; invalid parameter\n",
parm->tm_lim);
if (parm->out_frq < 0)
xerror("glp_intopt: out_frq = %d; invalid parameter\n",
parm->out_frq);
if (parm->out_dly < 0)
xerror("glp_intopt: out_dly = %d; invalid parameter\n",
parm->out_dly);
if (!(0 <= parm->cb_size && parm->cb_size <= 256))
xerror("glp_intopt: cb_size = %d; invalid parameter\n",
parm->cb_size);
if (!(parm->pp_tech == GLP_PP_NONE ||
parm->pp_tech == GLP_PP_ROOT ||
parm->pp_tech == GLP_PP_ALL))
xerror("glp_intopt: pp_tech = %d; invalid parameter\n",
parm->pp_tech);
if (parm->mip_gap < 0.0)
xerror("glp_intopt: mip_gap = %g; invalid parameter\n",
parm->mip_gap);
if (!(parm->mir_cuts == GLP_ON || parm->mir_cuts == GLP_OFF))
xerror("glp_intopt: mir_cuts = %d; invalid parameter\n",
parm->mir_cuts);
if (!(parm->gmi_cuts == GLP_ON || parm->gmi_cuts == GLP_OFF))
xerror("glp_intopt: gmi_cuts = %d; invalid parameter\n",
parm->gmi_cuts);
if (!(parm->cov_cuts == GLP_ON || parm->cov_cuts == GLP_OFF))
xerror("glp_intopt: cov_cuts = %d; invalid parameter\n",
parm->cov_cuts);
if (!(parm->clq_cuts == GLP_ON || parm->clq_cuts == GLP_OFF))
xerror("glp_intopt: clq_cuts = %d; invalid parameter\n",
parm->clq_cuts);
if (!(parm->presolve == GLP_ON || parm->presolve == GLP_OFF))
xerror("glp_intopt: presolve = %d; invalid parameter\n",
parm->presolve);
if (!(parm->binarize == GLP_ON || parm->binarize == GLP_OFF))
xerror("glp_intopt: binarize = %d; invalid parameter\n",
parm->binarize);
if (!(parm->fp_heur == GLP_ON || parm->fp_heur == GLP_OFF))
xerror("glp_intopt: fp_heur = %d; invalid parameter\n",
parm->fp_heur);
#if 1 /* 28/V-2010 */
if (!(parm->alien == GLP_ON || parm->alien == GLP_OFF))
xerror("glp_intopt: alien = %d; invalid parameter\n",
parm->alien);
#endif
#if 0 /* 11/VII-2013 */
/* integer solution is currently undefined */
P->mip_stat = GLP_UNDEF;
P->mip_obj = 0.0;
#else
if (!parm->use_sol)
P->mip_stat = GLP_UNDEF;
if (P->mip_stat == GLP_NOFEAS)
P->mip_stat = GLP_UNDEF;
if (P->mip_stat == GLP_UNDEF)
P->mip_obj = 0.0;
else if (P->mip_stat == GLP_OPT)
P->mip_stat = GLP_FEAS;
#endif
/* check bounds of double-bounded variables */
for (i = 1; i <= P->m; i++)
{ GLPROW *row = P->row[i];
if (row->type == GLP_DB && row->lb >= row->ub)
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: row %d: lb = %g, ub = %g; incorrect"
" bounds\n", i, row->lb, row->ub);
ret = GLP_EBOUND;
goto done;
}
}
for (j = 1; j <= P->n; j++)
{ GLPCOL *col = P->col[j];
if (col->type == GLP_DB && col->lb >= col->ub)
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: column %d: lb = %g, ub = %g; incorr"
"ect bounds\n", j, col->lb, col->ub);
ret = GLP_EBOUND;
goto done;
}
}
/* bounds of all integer variables must be integral */
for (j = 1; j <= P->n; j++)
{ GLPCOL *col = P->col[j];
if (col->kind != GLP_IV) continue;
if (col->type == GLP_LO || col->type == GLP_DB)
{ if (col->lb != floor(col->lb))
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: integer column %d has non-intege"
"r lower bound %g\n", j, col->lb);
ret = GLP_EBOUND;
goto done;
}
}
if (col->type == GLP_UP || col->type == GLP_DB)
{ if (col->ub != floor(col->ub))
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: integer column %d has non-intege"
"r upper bound %g\n", j, col->ub);
ret = GLP_EBOUND;
goto done;
}
}
if (col->type == GLP_FX)
{ if (col->lb != floor(col->lb))
{ if (parm->msg_lev >= GLP_MSG_ERR)
xprintf("glp_intopt: integer column %d has non-intege"
"r fixed value %g\n", j, col->lb);
ret = GLP_EBOUND;
goto done;
}
}
}
/* solve MIP problem */
if (parm->msg_lev >= GLP_MSG_ALL)
{ int ni = glp_get_num_int(P);
int nb = glp_get_num_bin(P);
char s[50];
xprintf("GLPK Integer Optimizer, v%s\n", glp_version());
xprintf("%d row%s, %d column%s, %d non-zero%s\n",
P->m, P->m == 1 ? "" : "s", P->n, P->n == 1 ? "" : "s",
P->nnz, P->nnz == 1 ? "" : "s");
if (nb == 0)
strcpy(s, "none of");
else if (ni == 1 && nb == 1)
strcpy(s, "");
else if (nb == 1)
strcpy(s, "one of");
else if (nb == ni)
strcpy(s, "all of");
else
sprintf(s, "%d of", nb);
xprintf("%d integer variable%s, %s which %s binary\n",
ni, ni == 1 ? "" : "s", s, nb == 1 ? "is" : "are");
}
#if 1 /* 28/V-2010 */
if (parm->alien)
{ /* use alien integer optimizer */
ret = _glp_intopt1(P, parm);
goto done;
}
#endif
if (!parm->presolve)
#if 0 /* 11/VII-2013 */
ret = solve_mip(P, parm);
#else
ret = solve_mip(P, parm, P, NULL);
#endif
else
ret = preprocess_and_solve_mip(P, parm);
done: /* return to the application program */
return ret;
}
/***********************************************************************
* NAME
*
* glp_init_iocp - initialize integer optimizer control parameters
*
* SYNOPSIS
*
* void glp_init_iocp(glp_iocp *parm);
*
* DESCRIPTION
*
* The routine glp_init_iocp initializes control parameters, which are
* used by the integer optimizer, with default values.
*
* Default values of the control parameters are stored in a glp_iocp
* structure, which the parameter parm points to. */
void glp_init_iocp(glp_iocp *parm)
{ parm->msg_lev = GLP_MSG_ALL;
parm->br_tech = GLP_BR_DTH;
parm->bt_tech = GLP_BT_BLB;
parm->tol_int = 1e-5;
parm->tol_obj = 1e-7;
parm->tm_lim = INT_MAX;
parm->out_frq = 5000;
parm->out_dly = 10000;
parm->cb_func = NULL;
parm->cb_info = NULL;
parm->cb_size = 0;
parm->pp_tech = GLP_PP_ALL;
parm->mip_gap = 0.0;
parm->mir_cuts = GLP_OFF;
parm->gmi_cuts = GLP_OFF;
parm->cov_cuts = GLP_OFF;
parm->clq_cuts = GLP_OFF;
parm->presolve = GLP_OFF;
parm->binarize = GLP_OFF;
parm->fp_heur = GLP_OFF;
#if 1 /* 25/V-2013 */
parm->ps_heur = GLP_OFF;
#endif
#if 1 /* 29/VI-2013 */
parm->ps_tm_lim = 60000; /* 1 minute */
#endif
#if 1 /* 11/VII-2013 */
parm->use_sol = GLP_OFF;
parm->save_sol = NULL;
#endif
#if 1 /* 28/V-2010 */
parm->alien = GLP_OFF;
#endif
return;
}
/***********************************************************************
* NAME
*
* glp_mip_status - retrieve status of MIP solution
*
* SYNOPSIS
*
* int glp_mip_status(glp_prob *mip);
*
* RETURNS
*
* The routine lpx_mip_status reports the status of MIP solution found
* by the branch-and-bound solver as follows:
*
* GLP_UNDEF - MIP solution is undefined;
* GLP_OPT - MIP solution is integer optimal;
* GLP_FEAS - MIP solution is integer feasible but its optimality
* (or non-optimality) has not been proven, perhaps due to
* premature termination of the search;
* GLP_NOFEAS - problem has no integer feasible solution (proven by the
* solver). */
int glp_mip_status(glp_prob *mip)
{ int mip_stat = mip->mip_stat;
return mip_stat;
}
/***********************************************************************
* NAME
*
* glp_mip_obj_val - retrieve objective value (MIP solution)
*
* SYNOPSIS
*
* double glp_mip_obj_val(glp_prob *mip);
*
* RETURNS
*
* The routine glp_mip_obj_val returns value of the objective function
* for MIP solution. */
double glp_mip_obj_val(glp_prob *mip)
{ /*struct LPXCPS *cps = mip->cps;*/
double z;
z = mip->mip_obj;
/*if (cps->round && fabs(z) < 1e-9) z = 0.0;*/
return z;
}
/***********************************************************************
* NAME
*
* glp_mip_row_val - retrieve row value (MIP solution)
*
* SYNOPSIS
*
* double glp_mip_row_val(glp_prob *mip, int i);
*
* RETURNS
*
* The routine glp_mip_row_val returns value of the auxiliary variable
* associated with i-th row. */
double glp_mip_row_val(glp_prob *mip, int i)
{ /*struct LPXCPS *cps = mip->cps;*/
double mipx;
if (!(1 <= i && i <= mip->m))
xerror("glp_mip_row_val: i = %d; row number out of range\n", i)
;
mipx = mip->row[i]->mipx;
/*if (cps->round && fabs(mipx) < 1e-9) mipx = 0.0;*/
return mipx;
}
/***********************************************************************
* NAME
*
* glp_mip_col_val - retrieve column value (MIP solution)
*
* SYNOPSIS
*
* double glp_mip_col_val(glp_prob *mip, int j);
*
* RETURNS
*
* The routine glp_mip_col_val returns value of the structural variable
* associated with j-th column. */
double glp_mip_col_val(glp_prob *mip, int j)
{ /*struct LPXCPS *cps = mip->cps;*/
double mipx;
if (!(1 <= j && j <= mip->n))
xerror("glp_mip_col_val: j = %d; column number out of range\n",
j);
mipx = mip->col[j]->mipx;
/*if (cps->round && fabs(mipx) < 1e-9) mipx = 0.0;*/
return mipx;
}
/* eof */