int main(int argc, char *argv[])
{ LPX *lp;
MPL *mpl = NULL;
int ret;
double start;
/* parse command line parameters */
parse_cmdline(argc, argv);
/* remove all output files specified in the command line */
if (display != NULL) remove(display);
if (out_sol != NULL) remove(out_sol);
if (out_bnds != NULL) remove(out_bnds);
if (out_mps != NULL) remove(out_mps);
if (out_lpt != NULL) remove(out_lpt);
if (out_txt != NULL) remove(out_txt);
if (out_glp != NULL) remove(out_glp);
/* read problem from the input file */
if (in_file == NULL)
{ print("No input file specified; try %s --help", argv[0]);
exit(EXIT_FAILURE);
}
switch (format)
{ case 0:
lp = lpx_read_mps(in_file);
if (lp == NULL)
{ print("MPS file processing error");
exit(EXIT_FAILURE);
}
break;
case 1:
lp = lpx_read_lpt(in_file);
if (lp == NULL)
{ print("CPLEX LP file processing error");
exit(EXIT_FAILURE);
}
break;
case 2:
#if 0 /* 01/VIII-2004 */
lp = lpx_read_model(in_file, in_data, display);
if (lp == NULL)
{ print("Model processing error");
exit(EXIT_FAILURE);
}
#else
/* initialize the translator database */
mpl = mpl_initialize();
/* read model section and optional data section */
ret = mpl_read_model(mpl, in_file, in_data != NULL);
if (ret == 4)
err: { print("Model processing error");
exit(EXIT_FAILURE);
}
insist(ret == 1 || ret == 2);
/* read data section, if necessary */
if (in_data != NULL)
{ insist(ret == 1);
ret = mpl_read_data(mpl, in_data);
if (ret == 4) goto err;
insist(ret == 2);
}
/* generate model */
ret = mpl_generate(mpl, display);
if (ret == 4) goto err;
/* extract problem instance */
lp = lpx_extract_prob(mpl);
insist(lp != NULL);
#endif
if (lpx_get_num_rows(lp) == 0)
{ print("Problem has no rows");
exit(EXIT_FAILURE);
}
if (lpx_get_num_cols(lp) == 0)
{ print("Problem has no columns");
exit(EXIT_FAILURE);
}
break;
case 3:
lp = lpx_read_prob(in_file);
if (lp == NULL)
{ print("GNU LP file processing error");
exit(EXIT_FAILURE);
}
break;
default:
insist(format != format);
}
/* change problem name (if required) */
if (newname != NULL) lpx_set_prob_name(lp, newname);
/* change optimization direction (if required) */
if (dir != 0) lpx_set_obj_dir(lp, dir);
/* write problem in MPS format (if required) */
if (out_mps != NULL)
{ lpx_set_int_parm(lp, LPX_K_MPSORIG, orig);
ret = lpx_write_mps(lp, out_mps);
if (ret != 0)
{ print("Unable to write problem in MPS format");
exit(EXIT_FAILURE);
}
}
/* write problem in CPLEX LP format (if required) */
if (out_lpt != NULL)
{ lpx_set_int_parm(lp, LPX_K_LPTORIG, orig);
ret = lpx_write_lpt(lp, out_lpt);
if (ret != 0)
{ print("Unable to write problem in CPLEX LP format");
exit(EXIT_FAILURE);
}
}
/* write problem in plain text format (if required) */
if (out_txt != NULL)
{ lpx_set_int_parm(lp, LPX_K_LPTORIG, orig);
ret = lpx_print_prob(lp, out_txt);
if (ret != 0)
{ print("Unable to write problem in plain text format");
exit(EXIT_FAILURE);
}
}
/* write problem in GNU LP format (if required) */
if (out_glp != NULL)
{ ret = lpx_write_prob(lp, out_glp);
if (ret != 0)
{ print("Unable to write problem in GNU LP format");
exit(EXIT_FAILURE);
}
}
/* if only data check is required, skip computations */
if (check) goto skip;
/* scale the problem data (if required) */
if (scale && (!presol || method == 1)) lpx_scale_prob(lp);
/* build advanced initial basis (if required) */
if (method == 0 && basis && !presol) lpx_adv_basis(lp);
/* set some control parameters, which might be changed in the
command line */
lpx_set_int_parm(lp, LPX_K_PRICE, price);
if (!relax) lpx_set_real_parm(lp, LPX_K_RELAX, 0.0);
lpx_set_int_parm(lp, LPX_K_PRESOL, presol);
lpx_set_int_parm(lp, LPX_K_BRANCH, branch);
lpx_set_int_parm(lp, LPX_K_BTRACK, btrack);
lpx_set_real_parm(lp, LPX_K_TMLIM, (double)tmlim);
/* solve the problem */
start = utime();
switch (method)
{ case 0:
if (nomip || lpx_get_class(lp) == LPX_LP)
{ ret = lpx_simplex(lp);
if (presol && ret != LPX_E_OK && out_sol != NULL)
print("If you need actual output for non-optimal solu"
"tion, use --nopresol");
}
else
{ method = 2;
lpx_simplex(lp);
if (!intopt)
lpx_integer(lp);
else
lpx_intopt(lp);
}
break;
case 1:
if (nomip || lpx_get_class(lp) == LPX_LP)
lpx_interior(lp);
else
{ print("Interior point method is not able to solve MIP pr"
"oblem; use --simplex");
exit(EXIT_FAILURE);
}
break;
default:
insist(method != method);
}
/* display statistics */
print("Time used: %.1f secs", utime() - start);
print("Memory used: %.1fM (%d bytes)",
(double)lib_env_ptr()->mem_tpeak / (double)(1024 * 1024),
lib_env_ptr()->mem_tpeak);
#if 1 /* 01/VIII-2004 */
if (mpl != NULL && mpl_has_solve_stmt(mpl))
{ int n, j, round;
/* store the solution to the translator database */
n = lpx_get_num_cols(lp);
round = lpx_get_int_parm(lp, LPX_K_ROUND);
lpx_set_int_parm(lp, LPX_K_ROUND, 1);
switch (method)
{ case 0:
for (j = 1; j <= n; j++)
mpl_put_col_value(mpl, j, lpx_get_col_prim(lp, j));
break;
case 1:
for (j = 1; j <= n; j++)
mpl_put_col_value(mpl, j, lpx_ipt_col_prim(lp, j));
break;
case 2:
for (j = 1; j <= n; j++)
mpl_put_col_value(mpl, j, lpx_mip_col_val(lp, j));
break;
default:
insist(method != method);
}
lpx_set_int_parm(lp, LPX_K_ROUND, round);
/* perform postsolving */
ret = mpl_postsolve(mpl, display);
if (ret == 4)
{ print("Model postsolving error");
exit(EXIT_FAILURE);
}
insist(ret == 3);
}
#endif
/* write problem solution found by the solver (if required) */
if (out_sol != NULL)
{ switch (method)
{ case 0:
ret = lpx_print_sol(lp, out_sol);
break;
case 1:
ret = lpx_print_ips(lp, out_sol);
break;
case 2:
ret = lpx_print_mip(lp, out_sol);
break;
default:
insist(method != method);
}
if (ret != 0)
{ print("Unable to write problem solution");
exit(EXIT_FAILURE);
}
}
/* write sensitivity bounds information (if required) */
if (out_bnds != NULL)
{ if (method != 0)
{ print("Cannot write sensitivity bounds information for inte"
"rior-point or MIP solution");
exit(EXIT_FAILURE);
}
ret = lpx_print_sens_bnds(lp, out_bnds);
if (ret != 0)
{ print("Unable to write sensitivity bounds information");
exit(EXIT_FAILURE);
}
}
skip: /* delete the problem object */
lpx_delete_prob(lp);
#if 1 /* 01/VIII-2004 */
/* if the translator database exists, destroy it */
if (mpl != NULL) mpl_terminate(mpl);
#endif
/* check that no memory blocks are still allocated */
insist(lib_env_ptr()->mem_total == 0);
insist(lib_env_ptr()->mem_count == 0);
/* return to the control program */
return 0;
}
int main(int argc, char *argv[])
{ LPX *lp;
MPL *mpl = NULL;
int ret;
ulong_t start;
/* parse command line parameters */
parse_cmdline(argc, argv);
/* set available memory limit */
if (memlim >= 0)
lib_mem_limit(ulmul(ulset(0, 1048576), ulset(0, memlim)));
/* remove all output files specified in the command line */
if (display != NULL) remove(display);
if (out_bas != NULL) remove(out_bas);
if (out_sol != NULL) remove(out_sol);
if (out_bnds != NULL) remove(out_bnds);
if (out_mps != NULL) remove(out_mps);
if (out_freemps != NULL) remove(out_freemps);
if (out_cpxlp != NULL) remove(out_cpxlp);
if (out_txt != NULL) remove(out_txt);
if (out_glp != NULL) remove(out_glp);
if (log_file != NULL) remove(log_file);
/* open hardcopy file, if necessary */
if (log_file != NULL)
{ if (lib_open_log(log_file))
{ print("Unable to create log file");
exit(EXIT_FAILURE);
}
}
/* read problem data from the input file */
if (in_file == NULL)
{ print("No input file specified; try %s --help", argv[0]);
exit(EXIT_FAILURE);
}
switch (format)
{ case 0:
lp = lpx_read_mps(in_file);
if (lp == NULL)
{ print("MPS file processing error");
exit(EXIT_FAILURE);
}
orig = 1;
break;
case 1:
lp = lpx_read_cpxlp(in_file);
if (lp == NULL)
{ print("CPLEX LP file processing error");
exit(EXIT_FAILURE);
}
break;
case 2:
/* initialize the translator database */
mpl = mpl_initialize();
/* read model section and optional data section */
ret = mpl_read_model(mpl, in_file, in_data != NULL);
if (ret == 4)
err: { print("Model processing error");
exit(EXIT_FAILURE);
}
xassert(ret == 1 || ret == 2);
/* read data section, if necessary */
if (in_data != NULL)
{ xassert(ret == 1);
ret = mpl_read_data(mpl, in_data);
if (ret == 4) goto err;
xassert(ret == 2);
}
/* generate model */
ret = mpl_generate(mpl, display);
if (ret == 4) goto err;
/* extract problem instance */
lp = lpx_extract_prob(mpl);
xassert(lp != NULL);
break;
case 3:
lp = lpx_read_prob(in_file);
if (lp == NULL)
{ print("GNU LP file processing error");
exit(EXIT_FAILURE);
}
break;
case 4:
lp = lpx_read_freemps(in_file);
if (lp == NULL)
{ print("MPS file processing error");
exit(EXIT_FAILURE);
}
break;
default:
xassert(format != format);
}
/* order rows and columns of the constraint matrix */
lpx_order_matrix(lp);
/* change problem name (if required) */
if (newname != NULL) lpx_set_prob_name(lp, newname);
/* change optimization direction (if required) */
if (dir != 0) lpx_set_obj_dir(lp, dir);
/* write problem in fixed MPS format (if required) */
if (out_mps != NULL)
{ lpx_set_int_parm(lp, LPX_K_MPSORIG, orig);
ret = lpx_write_mps(lp, out_mps);
if (ret != 0)
{ print("Unable to write problem in fixed MPS format");
exit(EXIT_FAILURE);
}
}
/* write problem in free MPS format (if required) */
if (out_freemps != NULL)
{ ret = lpx_write_freemps(lp, out_freemps);
if (ret != 0)
{ print("Unable to write problem in free MPS format");
exit(EXIT_FAILURE);
}
}
/* write problem in CPLEX LP format (if required) */
if (out_cpxlp != NULL)
{ ret = lpx_write_cpxlp(lp, out_cpxlp);
if (ret != 0)
{ print("Unable to write problem in CPLEX LP format");
exit(EXIT_FAILURE);
}
}
/* write problem in plain text format (if required) */
if (out_txt != NULL)
{ lpx_set_int_parm(lp, LPX_K_LPTORIG, orig);
ret = lpx_print_prob(lp, out_txt);
if (ret != 0)
{ print("Unable to write problem in plain text format");
exit(EXIT_FAILURE);
}
}
/* write problem in GNU LP format (if required) */
if (out_glp != NULL)
{ ret = lpx_write_prob(lp, out_glp);
if (ret != 0)
{ print("Unable to write problem in GNU LP format");
exit(EXIT_FAILURE);
}
}
/* if only data check is required, skip computations */
if (check) goto skip;
/* scale the problem data (if required) */
if (scale && (!presol || method == 1)) lpx_scale_prob(lp);
/* build initial LP basis */
if (method == 0 && !presol && in_bas == NULL)
{ switch (basis)
{ case 0:
lpx_std_basis(lp);
break;
case 1:
if (lpx_get_num_rows(lp) > 0 && lpx_get_num_cols(lp) > 0)
lpx_adv_basis(lp);
break;
case 2:
if (lpx_get_num_rows(lp) > 0 && lpx_get_num_cols(lp) > 0)
lpx_cpx_basis(lp);
break;
default:
xassert(basis != basis);
}
}
/* or read initial basis from input text file in MPS format */
if (in_bas != NULL)
{ if (method != 0)
{ print("Initial LP basis is useless for interior-point solve"
"r and therefore ignored");
goto nobs;
}
lpx_set_int_parm(lp, LPX_K_MPSORIG, orig);
ret = lpx_read_bas(lp, in_bas);
if (ret != 0)
{ print("Unable to read initial LP basis");
exit(EXIT_FAILURE);
}
if (presol)
{ presol = 0;
print("LP presolver disabled because initial LP basis has b"
"een provided");
}
nobs: ;
}
/* set some control parameters, which might be changed in the
command line */
lpx_set_int_parm(lp, LPX_K_BFTYPE, bf_type);
lpx_set_int_parm(lp, LPX_K_PRICE, price);
if (!relax) lpx_set_real_parm(lp, LPX_K_RELAX, 0.0);
lpx_set_int_parm(lp, LPX_K_PRESOL, presol);
lpx_set_int_parm(lp, LPX_K_BRANCH, branch);
lpx_set_int_parm(lp, LPX_K_BTRACK, btrack);
lpx_set_real_parm(lp, LPX_K_TMLIM, (double)tmlim);
lpx_set_int_parm(lp, LPX_K_BINARIZE, binarize);
lpx_set_int_parm(lp, LPX_K_USECUTS, use_cuts);
/* solve the problem */
start = xtime();
switch (method)
{ case 0:
if (nomip || lpx_get_class(lp) == LPX_LP)
{ ret = (!exact ? lpx_simplex(lp) : lpx_exact(lp));
if (xcheck)
{ if (!presol || ret == LPX_E_OK)
lpx_exact(lp);
else
print("If you need checking final basis for non-op"
"timal solution, use --nopresol");
}
if (presol && ret != LPX_E_OK && (out_bas != NULL ||
out_sol != NULL))
print("If you need actual output for non-optimal solu"
"tion, use --nopresol");
}
else
{ method = 2;
if (!intopt)
{ ret = (!exact ? lpx_simplex(lp) : lpx_exact(lp));
if (xcheck && (!presol || ret == LPX_E_OK))
lpx_exact(lp);
lpx_integer(lp);
}
else
lpx_intopt(lp);
}
break;
case 1:
if (nomip || lpx_get_class(lp) == LPX_LP)
lpx_interior(lp);
else
{ print("Interior-point method is not able to solve MIP pr"
"oblem; use --simplex");
exit(EXIT_FAILURE);
}
break;
default:
xassert(method != method);
}
/* display statistics */
print("Time used: %.1f secs", xdifftime(xtime(), start));
{ ulong_t tpeak;
char buf[50];
lib_mem_usage(NULL, NULL, NULL, &tpeak);
print("Memory used: %.1f Mb (%s bytes)",
(4294967296.0 * tpeak.hi + tpeak.lo) / 1048576.0,
ultoa(tpeak, buf, 10));
}
if (mpl != NULL && mpl_has_solve_stmt(mpl))
{ int n, j, round;
/* store the solution to the translator database */
n = lpx_get_num_cols(lp);
round = lpx_get_int_parm(lp, LPX_K_ROUND);
lpx_set_int_parm(lp, LPX_K_ROUND, 1);
switch (method)
{ case 0:
for (j = 1; j <= n; j++)
mpl_put_col_value(mpl, j, lpx_get_col_prim(lp, j));
break;
case 1:
for (j = 1; j <= n; j++)
mpl_put_col_value(mpl, j, lpx_ipt_col_prim(lp, j));
break;
case 2:
for (j = 1; j <= n; j++)
mpl_put_col_value(mpl, j, lpx_mip_col_val(lp, j));
break;
default:
xassert(method != method);
}
lpx_set_int_parm(lp, LPX_K_ROUND, round);
/* perform postsolving */
ret = mpl_postsolve(mpl);
if (ret == 4)
{ print("Model postsolving error");
exit(EXIT_FAILURE);
}
xassert(ret == 3);
}
/* write final LP basis (if required) */
if (out_bas != NULL)
{ lpx_set_int_parm(lp, LPX_K_MPSORIG, orig);
ret = lpx_write_bas(lp, out_bas);
if (ret != 0)
{ print("Unable to write final LP basis");
exit(EXIT_FAILURE);
}
}
/* write problem solution found by the solver (if required) */
if (out_sol != NULL)
{ switch (method)
{ case 0:
ret = lpx_print_sol(lp, out_sol);
break;
case 1:
ret = lpx_print_ips(lp, out_sol);
break;
case 2:
ret = lpx_print_mip(lp, out_sol);
break;
default:
xassert(method != method);
}
if (ret != 0)
{ print("Unable to write problem solution");
exit(EXIT_FAILURE);
}
}
/* write sensitivity bounds information (if required) */
if (out_bnds != NULL)
{ if (method != 0)
{ print("Cannot write sensitivity bounds information for inte"
"rior-point or MIP solution");
exit(EXIT_FAILURE);
}
ret = lpx_print_sens_bnds(lp, out_bnds);
if (ret != 0)
{ print("Unable to write sensitivity bounds information");
exit(EXIT_FAILURE);
}
}
skip: /* delete the problem object */
lpx_delete_prob(lp);
/* if the translator database exists, destroy it */
if (mpl != NULL) mpl_terminate(mpl);
xassert(gmp_pool_count() == 0);
gmp_free_mem();
/* close the hardcopy file */
if (log_file != NULL) lib_close_log();
/* check that no memory blocks are still allocated */
{ int count;
ulong_t total;
lib_mem_usage(&count, NULL, &total, NULL);
xassert(count == 0);
xassert(total.lo == 0 && total.hi == 0);
}
/* free the library environment */
lib_free_env();
/* return to the control program */
return 0;
}
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;
}
static PyObject* LPX_solver_integer(LPXObject *self, PyObject *args,
PyObject *keywds) {
#if GLPK_VERSION(4, 20)
PyObject *callback=NULL;
struct mip_callback_object*info=NULL;
glp_iocp cp;
glp_init_iocp(&cp);
cp.msg_lev = GLP_MSG_OFF;
// Map the keyword arguments to the appropriate entries.
static char *kwlist[] =
{"msg_lev", "br_tech", "bt_tech",
#if GLPK_VERSION(4, 21)
"pp_tech",
#endif // GLPK_VERSION(4, 21)
#if GLPK_VERSION(4, 24)
"gmi_cuts",
#endif // GLPK_VERSION(4, 24)
#if GLPK_VERSION(4, 23)
"mir_cuts",
"mip_gap",
#endif // GLPK_VERSION(4, 23)
#if GLPK_VERSION(4, 32)
"cov_cuts", "clq_cuts", "presolve", "binarize",
#endif // GLPK_VERSION(4, 32)
#if GLPK_VERSION(4, 37)
"fp_heur",
#endif // GLPK_VERSION(4, 37)
"tol_int", "tol_obj", "tm_lim", "out_frq", "out_dly",
"callback", //"cb_info", "cb_size",
NULL};
if (!PyArg_ParseTupleAndKeywords
(args, keywds, "|iii"
#if GLPK_VERSION(4, 21)
"i"
#endif // GLPK_VERSION(4, 21)
#if GLPK_VERSION(4, 24)
"i"
#endif // GLPK_VERSION(4, 24)
#if GLPK_VERSION(4, 23)
"ii"
#endif // GLPK_VERSION(4, 23)
#if GLPK_VERSION(4, 32)
"iiii"
#endif // GLPK_VERSION(4, 32)
#if GLPK_VERSION(4, 37)
"i"
#endif // GLPK_VERSION(4, 37)
"ddiiiO", kwlist, &cp.msg_lev, &cp.br_tech, &cp.bt_tech,
#if GLPK_VERSION(4, 21)
&cp.pp_tech,
#endif // GLPK_VERSION(4, 21)
#if GLPK_VERSION(4, 24)
&cp.gmi_cuts,
#endif // GLPK_VERSION(4, 24)
#if GLPK_VERSION(4, 23)
&cp.mir_cuts,
&cp.mip_gap,
#endif // GLPK_VERSION(4, 23)
#if GLPK_VERSION(4, 32)
&cp.cov_cuts, &cp.clq_cuts, &cp.presolve, &cp.binarize,
#endif // GLPK_VERSION(4, 32)
#if GLPK_VERSION(4, 37)
&cp.fp_heur,
#endif // GLPK_VERSION(4, 37)
&cp.tol_int, &cp.tol_obj, &cp.tm_lim, &cp.out_frq, &cp.out_dly,
&callback)) {
return NULL;
}
#if GLPK_VERSION(4, 24)
cp.gmi_cuts = cp.gmi_cuts ? GLP_ON : GLP_OFF;
#endif // GLPK_VERSION(4, 24)
#if GLPK_VERSION(4, 23)
cp.mir_cuts = cp.mir_cuts ? GLP_ON : GLP_OFF;
#endif // GLPK_VERSION(4, 23)
#if GLPK_VERSION(4, 32)
cp.cov_cuts = cp.cov_cuts ? GLP_ON : GLP_OFF;
cp.clq_cuts = cp.clq_cuts ? GLP_ON : GLP_OFF;
cp.presolve = cp.presolve ? GLP_ON : GLP_OFF;
cp.binarize = cp.binarize ? GLP_ON : GLP_OFF;
#endif // GLPK_VERSION(4, 32)
#if GLPK_VERSION(4, 37)
cp.fp_heur = cp.fp_heur ? GLP_ON : GLP_OFF;
#endif // GLPK_VERSION(4, 32)
// Do checking on the various entries.
#if GLPK_VERSION(4, 32)
if (!cp.presolve && glp_get_status(LP) != GLP_OPT) {
PyErr_SetString(PyExc_RuntimeError, "integer solver requires "
"use of presolver or existing optimal basic solution");
return NULL;
}
#else
if (glp_get_status(LP) != GLP_OPT) {
PyErr_SetString(PyExc_RuntimeError, "integer solver requires "
"existing optimal basic solution");
return NULL;
}
#endif
switch (cp.msg_lev) {
case GLP_MSG_OFF: case GLP_MSG_ERR: case GLP_MSG_ON: case GLP_MSG_ALL: break;
default:
PyErr_SetString
(PyExc_ValueError,
"invalid value for msg_lev (LPX.MSG_* are valid values)");
return NULL;
}
switch (cp.br_tech) {
case GLP_BR_FFV: case GLP_BR_LFV: case GLP_BR_MFV: case GLP_BR_DTH: break;
default:
PyErr_SetString
(PyExc_ValueError,
"invalid value for br_tech (LPX.BR_* are valid values)");
return NULL;
}
switch (cp.bt_tech) {
case GLP_BT_DFS: case GLP_BT_BFS: case GLP_BT_BLB: case GLP_BT_BPH: break;
default:
PyErr_SetString
(PyExc_ValueError,
"invalid value for bt_tech (LPX.BT_* are valid values)");
return NULL;
}
#if GLPK_VERSION(4, 21)
switch (cp.pp_tech) {
case GLP_PP_NONE: case GLP_PP_ROOT: case GLP_PP_ALL: break;
default:
PyErr_SetString
(PyExc_ValueError,
"invalid value for pp_tech (LPX.PP_* are valid values)");
return NULL;
}
#endif // GLPK_VERSION(4, 21)
if (cp.tol_int<=0 || cp.tol_int>=1) {
PyErr_SetString(PyExc_ValueError, "tol_int must obey 0<tol_int<1");
return NULL;
}
if (cp.tol_obj<=0 || cp.tol_obj>=1) {
PyErr_SetString(PyExc_ValueError, "tol_obj must obey 0<tol_obj<1");
return NULL;
}
if (cp.tm_lim<0) {
PyErr_SetString(PyExc_ValueError, "tm_lim must be non-negative");
return NULL;
}
if (cp.out_frq<=0) {
PyErr_SetString(PyExc_ValueError, "out_frq must be positive");
return NULL;
}
if (cp.out_dly<0) {
PyErr_SetString(PyExc_ValueError, "out_dly must be non-negative");
return NULL;
}
#if GLPK_VERSION(4, 23)
if (cp.mip_gap<0) {
PyErr_SetString(PyExc_ValueError, "mip_gap must be non-negative");
return NULL;
}
#endif
int retval;
if (callback != NULL && callback != Py_None) {
info = (struct mip_callback_object*)
malloc(sizeof(struct mip_callback_object));
info->callback = callback;
info->py_lp = self;
cp.cb_info = info;
cp.cb_func = mip_callback;
}
retval = glp_intopt(LP, &cp);
if (info) free(info);
if (PyErr_Occurred()) {
// This should happen only if there was a problem within the
// callback function, or if the callback was not appropriate.
return NULL;
}
if (retval!=GLP_EBADB && retval!=GLP_ESING && retval!=GLP_ECOND
&& retval!=GLP_EBOUND && retval!=GLP_EFAIL)
self->last_solver = 2;
return glpsolver_retval_to_message(retval);
#else
int retval = lpx_integer(LP);
if (retval!=LPX_E_FAULT) self->last_solver = 2;
return solver_retval_to_message(retval);
#endif // GLPK_VERSION(4, 20)
}
int lpx_intopt(LPX *_mip)
{ IPP *ipp = NULL;
LPX *orig = _mip, *prob = NULL;
int orig_m, orig_n, i, j, ret, i_stat;
/* the problem must be of MIP class */
if (lpx_get_class(orig) != LPX_MIP)
{ print("lpx_intopt: problem is not of MIP class");
ret = LPX_E_FAULT;
goto done;
}
/* the problem must have at least one row and one column */
orig_m = lpx_get_num_rows(orig);
orig_n = lpx_get_num_cols(orig);
if (!(orig_m > 0 && orig_n > 0))
{ print("lpx_intopt: problem has no rows/columns");
ret = LPX_E_FAULT;
goto done;
}
/* check that each double-bounded row and column has bounds */
for (i = 1; i <= orig_m; i++)
{ if (lpx_get_row_type(orig, i) == LPX_DB)
{ if (lpx_get_row_lb(orig, i) >= lpx_get_row_ub(orig, i))
{ print("lpx_intopt: row %d has incorrect bounds", i);
ret = LPX_E_FAULT;
goto done;
}
}
}
for (j = 1; j <= orig_n; j++)
{ if (lpx_get_col_type(orig, j) == LPX_DB)
{ if (lpx_get_col_lb(orig, j) >= lpx_get_col_ub(orig, j))
{ print("lpx_intopt: column %d has incorrect bounds", j);
ret = LPX_E_FAULT;
goto done;
}
}
}
/* bounds of all integer variables must be integral */
for (j = 1; j <= orig_n; j++)
{ int type;
double lb, ub;
if (lpx_get_col_kind(orig, j) != LPX_IV) continue;
type = lpx_get_col_type(orig, j);
if (type == LPX_LO || type == LPX_DB || type == LPX_FX)
{ lb = lpx_get_col_lb(orig, j);
if (lb != floor(lb))
{ print("lpx_intopt: integer column %d has non-integer low"
"er bound or fixed value %g", j, lb);
ret = LPX_E_FAULT;
goto done;
}
}
if (type == LPX_UP || type == LPX_DB)
{ ub = lpx_get_col_ub(orig, j);
if (ub != floor(ub))
{ print("lpx_intopt: integer column %d has non-integer upp"
"er bound %g", j, ub);
ret = LPX_E_FAULT;
goto done;
}
}
}
/* reset the status of MIP solution */
lpx_put_mip_soln(orig, LPX_I_UNDEF, NULL, NULL);
/* create MIP presolver workspace */
ipp = ipp_create_wksp();
/* load the original problem into the presolver workspace */
ipp_load_orig(ipp, orig);
/* perform basic MIP presolve analysis */
switch (ipp_basic_tech(ipp))
{ case 0:
/* no infeasibility is detected */
break;
case 1:
nopfs: /* primal infeasibility is detected */
print("PROBLEM HAS NO PRIMAL FEASIBLE SOLUTION");
ret = LPX_E_NOPFS;
goto done;
case 2:
/* dual infeasibility is detected */
nodfs: print("LP RELAXATION HAS NO DUAL FEASIBLE SOLUTION");
ret = LPX_E_NODFS;
goto done;
default:
insist(ipp != ipp);
}
/* reduce column bounds */
switch (ipp_reduce_bnds(ipp))
{ case 0: break;
case 1: goto nopfs;
default: insist(ipp != ipp);
}
/* perform basic MIP presolve analysis */
switch (ipp_basic_tech(ipp))
{ case 0: break;
case 1: goto nopfs;
case 2: goto nodfs;
default: insist(ipp != ipp);
}
/* replace general integer variables by sum of binary variables,
if required */
if (lpx_get_int_parm(orig, LPX_K_BINARIZE))
ipp_binarize(ipp);
/* perform coefficient reduction */
ipp_reduction(ipp);
/* if the resultant problem is empty, it has an empty solution,
which is optimal */
if (ipp->row_ptr == NULL || ipp->col_ptr == NULL)
{ insist(ipp->row_ptr == NULL);
insist(ipp->col_ptr == NULL);
print("Objective value = %.10g",
ipp->orig_dir == LPX_MIN ? +ipp->c0 : -ipp->c0);
print("INTEGER OPTIMAL SOLUTION FOUND BY MIP PRESOLVER");
/* allocate recovered solution segment */
ipp->col_stat = ucalloc(1+ipp->ncols, sizeof(int));
ipp->col_mipx = ucalloc(1+ipp->ncols, sizeof(double));
for (j = 1; j <= ipp->ncols; j++) ipp->col_stat[j] = 0;
/* perform MIP postsolve processing */
ipp_postsolve(ipp);
/* unload recovered MIP solution and store it in the original
problem object */
ipp_unload_sol(ipp, orig, LPX_I_OPT);
ret = LPX_E_OK;
goto done;
}
/* build resultant MIP problem object */
prob = ipp_build_prob(ipp);
/* display some statistics */
{ int m = lpx_get_num_rows(prob);
int n = lpx_get_num_cols(prob);
int nnz = lpx_get_num_nz(prob);
int ni = lpx_get_num_int(prob);
int nb = lpx_get_num_bin(prob);
char s[50];
print("lpx_intopt: presolved MIP has %d row%s, %d column%s, %d"
" non-zero%s", m, m == 1 ? "" : "s", n, n == 1 ? "" : "s",
nnz, 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);
print("lpx_intopt: %d integer column%s, %s which %s binary",
ni, ni == 1 ? "" : "s", s, nb == 1 ? "is" : "are");
}
/* inherit some control parameters and statistics */
lpx_set_int_parm(prob, LPX_K_PRICE, lpx_get_int_parm(orig,
LPX_K_PRICE));
lpx_set_real_parm(prob, LPX_K_RELAX, lpx_get_real_parm(orig,
LPX_K_RELAX));
lpx_set_real_parm(prob, LPX_K_TOLBND, lpx_get_real_parm(orig,
LPX_K_TOLBND));
lpx_set_real_parm(prob, LPX_K_TOLDJ, lpx_get_real_parm(orig,
LPX_K_TOLDJ));
lpx_set_real_parm(prob, LPX_K_TOLPIV, lpx_get_real_parm(orig,
LPX_K_TOLPIV));
lpx_set_int_parm(prob, LPX_K_ITLIM, lpx_get_int_parm(orig,
LPX_K_ITLIM));
lpx_set_int_parm(prob, LPX_K_ITCNT, lpx_get_int_parm(orig,
LPX_K_ITCNT));
lpx_set_real_parm(prob, LPX_K_TMLIM, lpx_get_real_parm(orig,
LPX_K_TMLIM));
lpx_set_int_parm(prob, LPX_K_BRANCH, lpx_get_int_parm(orig,
LPX_K_BRANCH));
lpx_set_int_parm(prob, LPX_K_BTRACK, lpx_get_int_parm(orig,
LPX_K_BTRACK));
lpx_set_real_parm(prob, LPX_K_TOLINT, lpx_get_real_parm(orig,
LPX_K_TOLINT));
lpx_set_real_parm(prob, LPX_K_TOLOBJ, lpx_get_real_parm(orig,
LPX_K_TOLOBJ));
/* build an advanced initial basis */
lpx_adv_basis(prob);
/* solve LP relaxation */
print("Solving LP relaxation...");
switch (lpx_simplex(prob))
{ case LPX_E_OK:
break;
case LPX_E_ITLIM:
ret = LPX_E_ITLIM;
goto done;
case LPX_E_TMLIM:
ret = LPX_E_TMLIM;
goto done;
default:
print("lpx_intopt: cannot solve LP relaxation");
ret = LPX_E_SING;
goto done;
}
/* analyze status of the basic solution */
switch (lpx_get_status(prob))
{ case LPX_OPT:
break;
case LPX_NOFEAS:
ret = LPX_E_NOPFS;
goto done;
case LPX_UNBND:
ret = LPX_E_NODFS;
goto done;
default:
insist(prob != prob);
}
/* generate cutting planes, if necessary */
if (lpx_get_int_parm(orig, LPX_K_USECUTS))
{ ret = generate_cuts(prob);
if (ret != LPX_E_OK) goto done;
}
/* call the branch-and-bound solver */
ret = lpx_integer(prob);
/* determine status of MIP solution */
i_stat = lpx_mip_status(prob);
if (i_stat == LPX_I_OPT || i_stat == LPX_I_FEAS)
{ /* load MIP solution of the resultant problem into presolver
workspace */
ipp_load_sol(ipp, prob);
/* perform MIP postsolve processing */
ipp_postsolve(ipp);
/* unload recovered MIP solution and store it in the original
problem object */
ipp_unload_sol(ipp, orig, i_stat);
}
else
{ /* just set the status of MIP solution */
lpx_put_mip_soln(orig, i_stat, NULL, NULL);
}
done: /* copy back statistics about spent resources */
if (prob != NULL)
{ lpx_set_int_parm(orig, LPX_K_ITLIM, lpx_get_int_parm(prob,
LPX_K_ITLIM));
lpx_set_int_parm(orig, LPX_K_ITCNT, lpx_get_int_parm(prob,
LPX_K_ITCNT));
lpx_set_real_parm(orig, LPX_K_TMLIM, lpx_get_real_parm(prob,
LPX_K_TMLIM));
}
/* delete the resultant problem object */
if (prob != NULL) lpx_delete_prob(prob);
/* delete MIP presolver workspace */
if (ipp != NULL) ipp_delete_wksp(ipp);
return ret;
}
