OptSolutionData* GLPKRunSolver(int ProbType) {
OptSolutionData* NewSolution = NULL;
int NumVariables = lpx_get_num_cols(GLPKModel);
int Status = 0;
if (ProbType == MILP) {
Status = lpx_simplex(GLPKModel);
if (Status != LPX_E_OK) {
FErrorFile() << "Failed to optimize problem." << endl;
FlushErrorFile();
return NULL;
}
Status = lpx_integer(GLPKModel);
if (Status != LPX_E_OK) {
FErrorFile() << "Failed to optimize problem." << endl;
FlushErrorFile();
return NULL;
}
NewSolution = new OptSolutionData;
Status = lpx_mip_status(GLPKModel);
if (Status == LPX_I_UNDEF || Status == LPX_I_NOFEAS) {
NewSolution->Status = INFEASIBLE;
return NewSolution;
} else if (Status == LPX_I_FEAS) {
NewSolution->Status = UNBOUNDED;
return NewSolution;
} else if (Status == LPX_I_OPT) {
NewSolution->Status = SUCCESS;
} else {
delete NewSolution;
FErrorFile() << "Problem status unrecognized." << endl;
FlushErrorFile();
return NULL;
}
NewSolution->Objective = lpx_mip_obj_val(GLPKModel);
NewSolution->SolutionData.resize(NumVariables);
for (int i=0; i < NumVariables; i++) {
NewSolution->SolutionData[i] = lpx_mip_col_val(GLPKModel, i+1);
}
} else if (ProbType == LP) {
//First we check the basis matrix to ensure it is not sigular
if (lpx_warm_up(GLPKModel) != LPX_E_OK) {
lpx_adv_basis(GLPKModel);
}
Status = lpx_simplex(GLPKModel);
if (Status == LPX_E_FAULT) {
Status = lpx_warm_up(GLPKModel);
if (Status == LPX_E_BADB) { /* the basis is invalid; build some valid basis */
lpx_adv_basis(GLPKModel);
Status = lpx_simplex(GLPKModel);
}
}
if (Status != LPX_E_OK) {
FErrorFile() << "Failed to optimize problem." << endl;
FlushErrorFile();
return NULL;
}
NewSolution = new OptSolutionData;
Status = lpx_get_status(GLPKModel);
if (Status == LPX_INFEAS || Status == LPX_NOFEAS || Status == LPX_UNDEF) {
cout << "Model is infeasible" << endl;
FErrorFile() << "Model is infeasible" << endl;
FlushErrorFile();
NewSolution->Status = INFEASIBLE;
return NewSolution;
} else if (Status == LPX_FEAS || Status == LPX_UNBND) {
cout << "Model is unbounded" << endl;
FErrorFile() << "Model is unbounded" << endl;
FlushErrorFile();
NewSolution->Status = UNBOUNDED;
return NewSolution;
} else if (Status == LPX_OPT) {
NewSolution->Status = SUCCESS;
} else {
delete NewSolution;
FErrorFile() << "Problem status unrecognized." << endl;
FlushErrorFile();
return NULL;
}
NewSolution->Objective = lpx_get_obj_val(GLPKModel);
NewSolution->SolutionData.resize(NumVariables);
for (int i=0; i < NumVariables; i++) {
NewSolution->SolutionData[i] = lpx_get_col_prim(GLPKModel, i+1);
}
} else {
FErrorFile() << "Optimization problem type cannot be handled by GLPK solver." << endl;
FlushErrorFile();
return NULL;
}
return NewSolution;
}
int lpx_print_sens_bnds(LPX *lp, char *fname)
{ FILE *fp = NULL;
int what, round;
print("lpx_print_sens_bnds: writing LP problem solution bounds to"
" `%s'...", fname);
#if 1
/* added by mao */
/* this routine needs factorization of the current basis matrix
which, however, does not exist if the basic solution was
obtained by the lp presolver; therefore we should warm up the
basis to be sure that the factorization is valid (note that if
the factorization exists, lpx_warm_up does nothing) */
lpx_warm_up(lp);
#endif
#if 0 /* 21/XII-2003 by mao */
if (lp->b_stat == LPX_B_UNDEF)
#else
if (!lpx_is_b_avail(lp))
#endif
{ print("lpx_print_sens_bnds: basis information not available (m"
"ay be a presolve issue)");
goto fail;
}
fp = ufopen(fname, "w");
if (fp == NULL)
{ print("lpx_print_sens_bnds: can't create `%s' - %s", fname,
strerror(errno));
goto fail;
}
/* problem name */
{ char *name;
name = lpx_get_prob_name(lp);
if (name == NULL) name = "";
fprintf(fp, "%-12s%s\n", "Problem:", name);
}
/* number of rows (auxiliary variables) */
{ int nr;
nr = lpx_get_num_rows(lp);
fprintf(fp, "%-12s%d\n", "Rows:", nr);
}
/* number of columns (structural variables) */
{ int nc;
nc = lpx_get_num_cols(lp);
fprintf(fp, "%-12s%d\n", "Columns:", nc);
}
/* number of non-zeros (constraint coefficients) */
{ int nz;
nz = lpx_get_num_nz(lp);
fprintf(fp, "%-12s%d\n", "Non-zeros:", nz);
}
/* solution status */
{ int status;
status = lpx_get_status(lp);
fprintf(fp, "%-12s%s\n", "Status:",
status == LPX_OPT ? "OPTIMAL" :
status == LPX_FEAS ? "FEASIBLE" :
status == LPX_INFEAS ? "INFEASIBLE (INTERMEDIATE)" :
status == LPX_NOFEAS ? "INFEASIBLE (FINAL)" :
status == LPX_UNBND ? "UNBOUNDED" :
status == LPX_UNDEF ? "UNDEFINED" : "???");
}
/* explanation/warning */
{ fprintf(fp, "\nExplanation: This file presents amounts by whi"
"ch objective coefficients,\n");
fprintf(fp, "constraint bounds, and variable bounds may be cha"
"nged in the original problem\n");
fprintf(fp, "while the optimal basis remains the same. Note t"
"hat the optimal solution\n");
fprintf(fp, "and objective value may change even though the ba"
"sis remains the same.\n");
fprintf(fp, "These bounds assume that all parameters remain fi"
"xed except the one in\n");
fprintf(fp, "question. If more than one parameter is changed,"
" it is possible for the\n");
fprintf(fp, "optimal basis to change even though each paramete"
"r stays within its bounds.\n");
fprintf(fp, "For more details, consult a text on linear progra"
"mming.\n");
}
/* Sensitivity ranges if solution was optimal */
{ int status;
status = lpx_get_status(lp);
if (status == LPX_OPT)
{ int i,j,k,m,n;
int dir;
double max_inc, max_dec;
int *index;
double *val;
fprintf(fp, "\nObjective Coefficient Analysis\n");
fprintf(fp, " No. Column name St Value Max incr"
"ease Max decrease\n");
fprintf(fp, "------ ------------ -- ------------- ---------"
"---- ------------- \n");
n = lpx_get_num_cols(lp);
m = lpx_get_num_rows(lp);
dir = lpx_get_obj_dir(lp);
/* allocate memory for index and val arrays */
index = ucalloc(1+n+m, sizeof(int));
val = ucalloc(1+n+m, sizeof(double));
for (j = 1; j <= n; j++)
{ char *name;
int typx, tagx;
double lb, ub, vx, dx;
name = lpx_get_col_name(lp, j);
if (name == NULL) name = "";
lpx_get_col_bnds(lp, j, &typx, &lb, &ub);
#if 0 /* 21/XII-2003 by mao */
round = lp->round, lp->round = 1;
lpx_get_col_info(lp, j, &tagx, &vx, &dx);
lp->round = round;
#else
round = lpx_get_int_parm(lp, LPX_K_ROUND);
lpx_set_int_parm(lp, LPX_K_ROUND, 1);
lpx_get_col_info(lp, j, &tagx, &vx, &dx);
lpx_set_int_parm(lp, LPX_K_ROUND, round);
#endif
/* row/column ordinal number */
fprintf(fp, "%6d ", j);
/* row column/name */
if (strlen(name) <= 12)
fprintf(fp, "%-12s ", name);
else
fprintf(fp, "%s\n%20s", name, "");
/* row/column status */
fprintf(fp, "%s ",
tagx == LPX_BS ? "B " :
tagx == LPX_NL ? "NL" :
tagx == LPX_NU ? "NU" :
tagx == LPX_NF ? "NF" :
tagx == LPX_NS ? "NS" : "??");
/* objective coefficient */
fprintf(fp, "%13.6g ", lpx_get_obj_coef(lp, j));
if (tagx == LPX_NL)
{ if (dir==LPX_MIN)
{ /* reduced cost must be positive */
max_inc = DBL_MAX; /* really represents infinity */
max_dec = dx;
}
else
{ /* reduced cost must be negative */
max_inc = -dx;
max_dec = DBL_MAX; /* means infinity */
}
}
if (tagx == LPX_NU)
{ if (dir==LPX_MIN)
{ /* reduced cost must be negative */
max_inc = -dx;
max_dec = DBL_MAX;
}
else
{ max_inc = DBL_MAX;
max_dec = dx;
}
}
if (tagx == LPX_NF)
{ /* can't change nonbasic free variables' cost */
max_inc = 0.0;
max_dec = 0.0;
}
if (tagx == LPX_NS)
{ /* doesn't matter what happens to the cost */
max_inc = DBL_MAX;
max_dec = DBL_MAX;
}
if (tagx == LPX_BS)
{ int len;
/* We need to see how this objective coefficient
affects reduced costs of other variables */
len = lpx_eval_tab_row(lp, m+j, index, val);
max_inc = DBL_MAX;
max_dec = DBL_MAX;
for (i = 1; i <= len; i++)
{ /*int stat;*/
int tagx2;
double vx2, dx2;
double delta;
if (index[i]>m)
lpx_get_col_info(lp, index[i]-m, &tagx2, &vx2,
&dx2);
else
lpx_get_row_info(lp, index[i], &tagx2, &vx2,
&dx2);
if (tagx2 == LPX_NL)
{ if (val[i] != 0.0)
{ delta = dx2 / val[i];
if (delta < 0 && -delta < max_inc)
max_inc = -delta;
else if (delta >0 && delta < max_dec)
max_dec = delta;
}
}
if (tagx2 == LPX_NU)
{ if (val[i] != 0.0)
{ delta = dx2 / val[i];
if (delta < 0 && -delta < max_inc)
max_inc = -delta;
else if (delta > 0 && delta < max_dec)
max_dec = delta;
}
}
if (tagx2 == LPX_NF)
{ if (val[i] != 0.0)
{ max_inc = 0.0;
max_dec = 0.0;
}
}
}
}
if (max_inc == -0.0) max_inc = 0.0;
if (max_dec == -0.0) max_dec = 0.0;
if (max_inc == DBL_MAX)
fprintf(fp, "%13s ", "infinity");
else if (max_inc < 1.0e-12 && max_inc > 0)
fprintf(fp, "%13s ", "< eps");
else
fprintf(fp, "%13.6g ", max_inc);
if (max_dec == DBL_MAX)
fprintf(fp, "%13s ", "infinity");
else if (max_dec < 1.0e-12 && max_dec > 0)
fprintf(fp, "%13s ", "< eps");
else
fprintf(fp, "%13.6g ", max_dec);
fprintf(fp, "\n");
}
for (what = 1; what <= 2; what++)
{ int ij, mn;
fprintf(fp, "\n");
fprintf(fp, "%s Analysis\n",
what==1? "Constraint Bounds":"Variable Bounds");
fprintf(fp, " No. %12s St Value Max increase "
" Max decrease\n",
what==1 ? " Row name":"Column name");
fprintf(fp, "------ ------------ -- ------------- ------"
"------- ------------- \n");
mn = what==1 ? m : n;
for (ij = 1; ij <= mn; ij++)
{ char *name;
int typx, tagx;
double lb, ub, vx, dx;
if (what==1)
name = lpx_get_row_name(lp, ij);
else
name = lpx_get_col_name(lp, ij);
if (name == NULL) name = "";
#if 0 /* 21/XII-2003 by mao */
if (what==1)
{ lpx_get_row_bnds(lp, ij, &typx, &lb, &ub);
round = lp->round, lp->round = 1;
lpx_get_row_info(lp, ij, &tagx, &vx, &dx);
lp->round = round;
}
else
{ lpx_get_col_bnds(lp, ij, &typx, &lb, &ub);
round = lp->round, lp->round = 1;
lpx_get_col_info(lp, ij, &tagx, &vx, &dx);
lp->round = round;
}
#else
round = lpx_get_int_parm(lp, LPX_K_ROUND);
lpx_set_int_parm(lp, LPX_K_ROUND, 1);
if (what==1)
{ lpx_get_row_bnds(lp, ij, &typx, &lb, &ub);
lpx_get_row_info(lp, ij, &tagx, &vx, &dx);
}
else
{ lpx_get_col_bnds(lp, ij, &typx, &lb, &ub);
lpx_get_col_info(lp, ij, &tagx, &vx, &dx);
}
lpx_set_int_parm(lp, LPX_K_ROUND, round);
#endif
/* row/column ordinal number */
fprintf(fp, "%6d ", ij);
/* row column/name */
if (strlen(name) <= 12)
fprintf(fp, "%-12s ", name);
else
fprintf(fp, "%s\n%20s", name, "");
/* row/column status */
fprintf(fp, "%s ",
tagx == LPX_BS ? "B " :
tagx == LPX_NL ? "NL" :
tagx == LPX_NU ? "NU" :
tagx == LPX_NF ? "NF" :
tagx == LPX_NS ? "NS" : "??");
fprintf(fp, "\n");
/* first check lower bound */
if (typx == LPX_LO || typx == LPX_DB ||
typx == LPX_FX)
{ int at_lower;
at_lower = 0;
if (tagx == LPX_BS || tagx == LPX_NU)
{ max_inc = vx - lb;
max_dec = DBL_MAX;
}
if (tagx == LPX_NS)
{ max_inc = 0.0;
max_dec = 0.0;
if (dir == LPX_MIN && dx > 0) at_lower = 1;
if (dir == LPX_MAX && dx < 0) at_lower = 1;
}
if (tagx == LPX_NL || at_lower == 1)
{ int len;
/* we have to see how it affects basic
variables */
len = lpx_eval_tab_col(lp, what==1?ij:ij+m,
index, val);
k = lpx_prim_ratio_test(lp, len, index, val, 1,
10e-7);
max_inc = DBL_MAX;
if (k != 0)
{ /*int stat;*/
int tagx2, typx2;
double vx2, dx2, lb2, ub2;
/*double delta;*/
double alpha;
int l;
for (l = 1; l <= len; l++)
if (index[l] == k) alpha = val[l];
if (k>m)
{ lpx_get_col_info(lp, k-m, &tagx2, &vx2,
&dx2);
lpx_get_col_bnds(lp, k-m, &typx2, &lb2,
&ub2);
}
else
{ lpx_get_row_info(lp, k, &tagx2, &vx2,
&dx2);
lpx_get_row_bnds(lp, k, &typx2, &lb2,
&ub2);
}
/* Check which direction;
remember this is upper bound */
if (alpha > 0)
max_inc = (ub2 - vx2)/ alpha;
else
max_inc = (lb2 - vx2)/ alpha;
}
/* now check lower bound */
k = lpx_prim_ratio_test(lp, len, index, val, -1,
10e-7);
max_dec = DBL_MAX;
if (k != 0)
{ /*int stat;*/
int tagx2, typx2;
double vx2, dx2, lb2, ub2;
/*double delta;*/
double alpha;
int l;
for (l = 1; l <= len; l++)
if (index[l] == k) alpha = val[l];
if (k>m)
{ lpx_get_col_info(lp, k-m, &tagx2, &vx2,
&dx2);
lpx_get_col_bnds(lp, k-m, &typx2, &lb2,
&ub2);
}
else
{ lpx_get_row_info(lp, k, &tagx2, &vx2,
&dx2);
lpx_get_row_bnds(lp, k, &typx2, &lb2,
&ub2);
}
/* Check which direction;
remember this is lower bound */
if (alpha > 0)
max_dec = (vx2 - lb2)/ alpha;
else
max_dec = (vx2 - ub2)/ alpha;
}
}
/* bound */
if (typx == LPX_DB || typx == LPX_FX)
{ if (max_inc > ub - lb)
max_inc = ub - lb;
}
fprintf(fp, " LOWER %13.6g ", lb);
if (max_inc == -0.0) max_inc = 0.0;
if (max_dec == -0.0) max_dec = 0.0;
if (max_inc == DBL_MAX)
fprintf(fp, "%13s ", "infinity");
else if (max_inc < 1.0e-12 && max_inc > 0)
fprintf(fp, "%13s ", "< eps");
else
fprintf(fp, "%13.6g ", max_inc);
if (max_dec == DBL_MAX)
fprintf(fp, "%13s ", "infinity");
else if (max_dec < 1.0e-12 && max_dec > 0)
fprintf(fp, "%13s ", "< eps");
else
fprintf(fp, "%13.6g ", max_dec);
fprintf(fp, "\n");
}
/* now check upper bound */
if (typx == LPX_UP || typx == LPX_DB ||
typx == LPX_FX)
{ int at_upper;
at_upper = 0;
if (tagx == LPX_BS || tagx == LPX_NL)
{ max_inc = DBL_MAX;
max_dec = ub - vx;
}
if (tagx == LPX_NS)
{ max_inc = 0.0;
max_dec = 0.0;
if (dir == LPX_MIN && dx < 0) at_upper = 1;
if (dir == LPX_MAX && dx > 0) at_upper = 1;
}
if (tagx == LPX_NU || at_upper == 1)
{ int len;
/* we have to see how it affects basic
variables */
len = lpx_eval_tab_col(lp, what==1?ij:ij+m,
index, val);
k = lpx_prim_ratio_test(lp, len, index, val, 1,
10e-7);
max_inc = DBL_MAX;
if (k != 0)
{ /*int stat;*/
int tagx2, typx2;
double vx2, dx2, lb2, ub2;
/*double delta;*/
double alpha;
int l;
for (l = 1; l <= len; l++)
if (index[l] == k) alpha = val[l];
if (k>m)
{ lpx_get_col_info(lp, k-m, &tagx2, &vx2,
&dx2);
lpx_get_col_bnds(lp, k-m, &typx2, &lb2,
&ub2);
}
else
{ lpx_get_row_info(lp, k, &tagx2, &vx2,
&dx2);
lpx_get_row_bnds(lp, k, &typx2, &lb2,
&ub2);
}
/* Check which direction;
remember this is upper bound */
if (alpha > 0)
max_inc = (ub2 - vx2)/ alpha;
else
max_inc = (lb2 - vx2)/ alpha;
}
/* now check lower bound */
k = lpx_prim_ratio_test(lp, len, index, val, -1,
10e-7);
max_dec = DBL_MAX;
if (k != 0)
{ /*int stat;*/
int tagx2, typx2;
double vx2, dx2, lb2, ub2;
/*double delta;*/
double alpha;
int l;
for (l = 1; l <= len; l++)
if (index[l] == k) alpha = val[l];
if (k>m)
{ lpx_get_col_info(lp, k-m, &tagx2, &vx2,
&dx2);
lpx_get_col_bnds(lp, k-m, &typx2, &lb2,
&ub2);
}
else
{ lpx_get_row_info(lp, k, &tagx2, &vx2,
&dx2);
lpx_get_row_bnds(lp, k, &typx2, &lb2,
&ub2);
}
/* Check which direction;
remember this is lower bound */
if (alpha > 0)
max_dec = (vx2 - lb2)/ alpha;
else
max_dec = (vx2 - ub2)/ alpha;
}
}
if (typx == LPX_DB || typx == LPX_FX)
{ if (max_dec > ub - lb)
max_dec = ub - lb;
}
/* bound */
fprintf(fp, " UPPER %13.6g ", ub);
if (max_inc == -0.0) max_inc = 0.0;
if (max_dec == -0.0) max_dec = 0.0;
if (max_inc == DBL_MAX)
fprintf(fp, "%13s ", "infinity");
else if (max_inc < 1.0e-12 && max_inc > 0)
fprintf(fp, "%13s ", "< eps");
else
fprintf(fp, "%13.6g ", max_inc);
if (max_dec == DBL_MAX)
fprintf(fp, "%13s ", "infinity");
else if (max_dec < 1.0e-12 && max_dec > 0)
fprintf(fp, "%13s ", "< eps");
else
fprintf(fp, "%13.6g ", max_dec);
fprintf(fp, "\n");
}
}
}
/* free the memory we used */
ufree(index);
ufree(val);
}
else fprintf(fp, "No range information since solution is not o"
"ptimal.\n");
}
fprintf(fp, "\n");
fprintf(fp, "End of output\n");
fflush(fp);
if (ferror(fp))
{ print("lpx_print_sens_bnds: can't write to `%s' - %s", fname,
strerror(errno));
goto fail;
}
ufclose(fp);
return 0;
fail: if (fp != NULL) ufclose(fp);
return 1;
}
