long GenModelCplex::WriteSolutionToFile(string filename)
{
if(!bcreated)
throw string("WriteSolutionToFile() not available : Problem not created yet;");
CplexData* d = static_cast<CplexData*>(solverdata);
CPXsolwrite (d->env, d->lp, filename.c_str());
return 0;
}
// Just write the solution in a file
int cplex_solver::writesol(char *filename) {
return CPXsolwrite(env, lp, filename);
}
int
main (int argc, char *argv[])
{
/* Declare and allocate space for the variables and arrays where we will
store the optimization results including the status, objective value,
maximum bound violation, variable values, and basis. */
time_t start, end;
/* returns elapsed time in sec */
// clock_t start, end;
/* for elapsed CPU time */
double total_time;
start = clock();
int solnstat, solnmethod, solntype;
double objval, maxviol;
double *x = NULL;
int *cstat = NULL;
int *rstat = NULL;
CPXENVptr env = NULL;
CPXLPptr lp = NULL;
int status = 0;
int j;
int cur_numrows, cur_numcols;
int method;
char *basismsg;
/* Check the command line arguments */
if (( argc != 4 ) ||
( strchr ("podhbnsc", argv[2][0]) == NULL ) ) {
usage (argv[0]);
goto TERMINATE;
}
/* Initialize the CPLEX environment */
env = CPXopenCPLEX (&status);
/* If an error occurs, the status value indicates the reason for
failure. A call to CPXgeterrorstring will produce the text of
the error message. Note that CPXopenCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPX_PARAM_SCRIND indicator is set to CPX_ON. */
if ( env == NULL ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not open CPLEX environment.\n");
CPXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
goto TERMINATE;
}
/* Turn on output to the screen */
status = CPXsetintparam (env, CPX_PARAM_SCRIND, CPX_ON);
if ( status ) {
fprintf (stderr,
"Failure to turn on screen indicator, error %d.\n", status);
goto TERMINATE;
}
/* Create the problem, using the filename as the problem name */
lp = CPXcreateprob (env, &status, argv[1]);
/* A returned pointer of NULL may mean that not enough memory
was available or there was some other problem. In the case of
failure, an error message will have been written to the error
channel from inside CPLEX. In this example, the setting of
the parameter CPX_PARAM_SCRIND causes the error message to
appear on stdout. Note that most CPLEX routines return
an error code to indicate the reason for failure. */
if ( lp == NULL ) {
fprintf (stderr, "Failed to create LP.\n");
goto TERMINATE;
}
/* Now read the file, and copy the data into the created lp */
status = CPXreadcopyprob (env, lp, argv[1], NULL);
if ( status ) {
fprintf (stderr, "Failed to read and copy the problem data.\n");
goto TERMINATE;
}
/* Optimize the problem and obtain solution. */
switch (argv[2][0]) {
case 'o':
method = CPX_ALG_AUTOMATIC;
break;
case 'p':
method = CPX_ALG_PRIMAL;
break;
case 'd':
method = CPX_ALG_DUAL;
break;
case 'n':
method = CPX_ALG_NET;
break;
case 'h':
method = CPX_ALG_BARRIER;
break;
case 'b':
method = CPX_ALG_BARRIER;
status = CPXsetintparam (env, CPX_PARAM_BARCROSSALG, CPX_ALG_NONE);
if ( status ) {
fprintf (stderr,
"Failed to set the crossover method, error %d.\n", status);
goto TERMINATE;
}
break;
case 's':
method = CPX_ALG_SIFTING;
break;
case 'c':
method = CPX_ALG_CONCURRENT;
break;
default:
method = CPX_ALG_NONE;
break;
}
status = CPXsetintparam (env, CPX_PARAM_LPMETHOD, method);
if ( status ) {
fprintf (stderr,
"Failed to set the optimization method, error %d.\n", status);
goto TERMINATE;
}
status = CPXlpopt (env, lp);
if ( status ) {
fprintf (stderr, "Failed to optimize LP.\n");
goto TERMINATE;
}
solnstat = CPXgetstat (env, lp);
if ( solnstat == CPX_STAT_UNBOUNDED ) {
printf ("Model is unbounded\n");
goto TERMINATE;
}
else if ( solnstat == CPX_STAT_INFEASIBLE ) {
printf ("Model is infeasible\n");
goto TERMINATE;
}
else if ( solnstat == CPX_STAT_INForUNBD ) {
printf ("Model is infeasible or unbounded\n");
goto TERMINATE;
}
status = CPXsolninfo (env, lp, &solnmethod, &solntype, NULL, NULL);
if ( status ) {
fprintf (stderr, "Failed to obtain solution info.\n");
goto TERMINATE;
}
printf ("Solution status %d, solution method %d\n", solnstat, solnmethod);
if ( solntype == CPX_NO_SOLN ) {
fprintf (stderr, "Solution not available.\n");
goto TERMINATE;
}
status = CPXgetobjval (env, lp, &objval);
if ( status ) {
fprintf (stderr, "Failed to obtain objective value.\n");
goto TERMINATE;
}
printf ("Objective value %.10g.\n", objval);
/* The size of the problem should be obtained by asking CPLEX what
the actual size is. cur_numrows and cur_numcols store the
current number of rows and columns, respectively. */
cur_numcols = CPXgetnumcols (env, lp);
cur_numrows = CPXgetnumrows (env, lp);
/* Retrieve basis, if one is available */
if ( solntype == CPX_BASIC_SOLN ) {
cstat = (int *) malloc (cur_numcols*sizeof(int));
rstat = (int *) malloc (cur_numrows*sizeof(int));
if ( cstat == NULL || rstat == NULL ) {
fprintf (stderr, "No memory for basis statuses.\n");
goto TERMINATE;
}
status = CPXgetbase (env, lp, cstat, rstat);
if ( status ) {
fprintf (stderr, "Failed to get basis; error %d.\n", status);
goto TERMINATE;
}
}
else {
printf ("No basis available\n");
}
/* Retrieve solution vector */
x = (double *) malloc (cur_numcols*sizeof(double));
if ( x == NULL ) {
fprintf (stderr, "No memory for solution.\n");
goto TERMINATE;
}
status = CPXgetx (env, lp, x, 0, cur_numcols-1);
if ( status ) {
fprintf (stderr, "Failed to obtain primal solution.\n");
goto TERMINATE;
}
status = CPXsolwrite(env,lp,argv[3]);
/* Write out the solution
for (j = 0; j < cur_numcols; j++) {
printf ( "Column %d: Value = %17.10g", j, x[j]);
if ( cstat != NULL ) {
switch (cstat[j]) {
case CPX_AT_LOWER:
basismsg = "Nonbasic at lower bound";
break;
case CPX_BASIC:
basismsg = "Basic";
break;
case CPX_AT_UPPER:
basismsg = "Nonbasic at upper bound";
break;
case CPX_FREE_SUPER:
basismsg = "Superbasic, or free variable at zero";
break;
default:
basismsg = "Bad basis status";
break;
}
printf (" %s",basismsg);
}
printf ("\n");
}
*/
/* Display the maximum bound violation. */
status = CPXgetdblquality (env, lp, &maxviol, CPX_MAX_PRIMAL_INFEAS);
if ( status ) {
fprintf (stderr, "Failed to obtain bound violation.\n");
goto TERMINATE;
}
printf ("Maximum bound violation = %17.10g\n", maxviol);
TERMINATE:
/* Free up the basis and solution */
free_and_null ((char **) &cstat);
free_and_null ((char **) &rstat);
free_and_null ((char **) &x);
/* Free up the problem, if necessary */
if ( lp != NULL ) {
status = CPXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXfreeprob failed, error code %d.\n", status);
}
}
/* Free up the CPLEX environment, if necessary */
if ( env != NULL ) {
status = CPXcloseCPLEX (&env);
/* Note that CPXcloseCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPX_PARAM_SCRIND indicator is set to CPX_ON. */
if ( status ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not close CPLEX environment.\n");
CPXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
}
}
end = clock();
total_time = (double)( end - start )/(double)CLOCKS_PER_SEC ;
printf( "\nElapsed time : %0.3f \n", total_time );
return (status);
} /* END main */
