int
main (void)
{
/* Declare pointers for the variables and arrays that will contain
the data which define the LP problem. The setproblemdata() routine
allocates space for the problem data. */
char *probname = NULL;
CPXDIM numcols;
CPXDIM numrows;
int objsen;
double *obj = NULL;
double *rhs = NULL;
char *sense = NULL;
CPXNNZ *matbeg = NULL;
CPXDIM *matcnt = NULL;
CPXDIM *matind = NULL;
double *matval = NULL;
double *lb = NULL;
double *ub = NULL;
CPXNNZ *qmatbeg = NULL;
CPXDIM *qmatcnt = NULL;
CPXDIM *qmatind = NULL;
double *qmatval = NULL;
/* Declare and allocate space for the variables and arrays where we
will store the optimization results including the status, objective
value, variable values, dual values, row slacks and variable
reduced costs. */
int solstat;
double objval;
double x[NUMCOLS];
double pi[NUMROWS];
double slack[NUMROWS];
double dj[NUMCOLS];
CPXENVptr env = NULL;
CPXLPptr lp = NULL;
int status;
CPXDIM i, j;
CPXDIM cur_numrows, cur_numcols;
/* Initialize the CPLEX environment */
env = CPXXopenCPLEX (&status);
/* If an error occurs, the status value indicates the reason for
failure. A call to CPXXgeterrorstring will produce the text of
the error message. Note that CPXXopenCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( env == NULL ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not open CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
goto TERMINATE;
}
/* Turn on output to the screen */
status = CPXXsetintparam (env, CPXPARAM_ScreenOutput, CPX_ON);
if ( status ) {
fprintf (stderr,
"Failure to turn on screen indicator, error %d.\n", status);
goto TERMINATE;
}
/* Fill in the data for the problem. */
status = setproblemdata (&probname, &numcols, &numrows, &objsen, &obj,
&rhs, &sense, &matbeg, &matcnt, &matind,
&matval, &lb, &ub, &qmatbeg, &qmatcnt,
&qmatind, &qmatval);
if ( status ) {
fprintf (stderr, "Failed to build problem data arrays.\n");
goto TERMINATE;
}
/* Create the problem. */
lp = CPXXcreateprob (env, &status, probname);
/* 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 CPXPARAM_ScreenOutput causes the error message to
appear on stdout. */
if ( lp == NULL ) {
fprintf (stderr, "Failed to create problem.\n");
goto TERMINATE;
}
/* Now copy the LP part of the problem data into the lp */
status = CPXXcopylp (env, lp, numcols, numrows, objsen, obj, rhs,
sense, matbeg, matcnt, matind, matval,
lb, ub, NULL);
if ( status ) {
fprintf (stderr, "Failed to copy problem data.\n");
goto TERMINATE;
}
status = CPXXcopyquad (env, lp, qmatbeg, qmatcnt, qmatind, qmatval);
if ( status ) {
fprintf (stderr, "Failed to copy quadratic matrix.\n");
goto TERMINATE;
}
/* Optimize the problem and obtain solution. */
status = CPXXqpopt (env, lp);
if ( status ) {
fprintf (stderr, "Failed to optimize QP.\n");
goto TERMINATE;
}
status = CPXXsolution (env, lp, &solstat, &objval, x, pi, slack, dj);
if ( status ) {
fprintf (stderr, "Failed to obtain solution.\n");
goto TERMINATE;
}
/* Write the output to the screen. */
printf ("\nSolution status = %d\n", solstat);
printf ("Solution value = %f\n\n", objval);
/* The size of the problem should be obtained by asking CPLEX what
the actual size is, rather than using what was passed to CPXXcopylp.
cur_numrows and cur_numcols store the current number of rows and
columns, respectively. */
cur_numrows = CPXXgetnumrows (env, lp);
cur_numcols = CPXXgetnumcols (env, lp);
for (i = 0; i < cur_numrows; i++) {
printf ("Row %d: Slack = %10f Pi = %10f\n", i, slack[i], pi[i]);
}
for (j = 0; j < cur_numcols; j++) {
printf ("Column %d: Value = %10f Reduced cost = %10f\n",
j, x[j], dj[j]);
}
/* Finally, write a copy of the problem to a file. */
status = CPXXwriteprob (env, lp, "qpex1.lp", NULL);
if ( status ) {
fprintf (stderr, "Failed to write LP to disk.\n");
goto TERMINATE;
}
TERMINATE:
/* Free up the problem as allocated by CPXXcreateprob, if necessary */
if ( lp != NULL ) {
status = CPXXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXXfreeprob failed, error code %d.\n", status);
}
}
/* Free up the CPLEX environment, if necessary */
if ( env != NULL ) {
status = CPXXcloseCPLEX (&env);
/* Note that CPXXcloseCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( status ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not close CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
}
}
/* Free up the problem data arrays, if necessary. */
free_and_null ((char **) &probname);
free_and_null ((char **) &obj);
free_and_null ((char **) &rhs);
free_and_null ((char **) &sense);
free_and_null ((char **) &matbeg);
free_and_null ((char **) &matcnt);
free_and_null ((char **) &matind);
free_and_null ((char **) &matval);
free_and_null ((char **) &lb);
free_and_null ((char **) &ub);
free_and_null ((char **) &qmatbeg);
free_and_null ((char **) &qmatcnt);
free_and_null ((char **) &qmatind);
free_and_null ((char **) &qmatval);
return (status);
} /* END main */
int
main (void)
{
/* Declare variables and arrays where we will store the
optimization results including the status, objective value,
and variable values. */
int solstat;
double objval;
CPXDIM colcnt = 0;
double *x = NULL;
CPXENVptr env = NULL;
CPXLPptr lp = NULL;
int status;
int m, p;
/* Initialize the CPLEX environment */
env = CPXXopenCPLEX (&status);
/* If an error occurs, the status value indicates the reason for
failure. A call to CPXXgeterrorstring will produce the text of
the error message. Note that CPXXopenCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( env == NULL ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not open CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
goto TERMINATE;
}
/* Turn on output to the screen */
status = CPXXsetintparam (env, CPXPARAM_ScreenOutput, CPX_ON);
if ( status ) {
fprintf (stderr,
"Failure to turn on screen indicator, error %d.\n", status);
goto TERMINATE;
}
/* Formulate and solve the problem */
lp = CPXXcreateprob (env, &status, "food manufacturing");
/* 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 CPXPARAM_ScreenOutput causes the error message to
appear on stdout. */
if ( lp == NULL ) {
fprintf (stderr, "Failed to create LP.\n");
goto TERMINATE;
}
/* Build the model */
status = buildmodel (env, lp);
if ( status ) {
fprintf (stderr, "Failed to build model.\n");
goto TERMINATE;
}
/* Write a copy of the problem to a file. */
status = CPXXwriteprob (env, lp, "foodmanu.lp", NULL);
if ( status ) {
fprintf (stderr, "Failed to write LP to disk.\n");
goto TERMINATE;
}
/* Optimize the problem and obtain solution. */
status = CPXXmipopt (env, lp);
if ( status ) {
fprintf (stderr, "Failed to optimize MIP.\n");
goto TERMINATE;
}
solstat = CPXXgetstat (env, lp);
/* Write solution status, objective and solution vector to the screen. */
printf ("\nSolution status = %d\n", solstat);
status = CPXXgetobjval (env, lp, &objval);
if ( status ) {
fprintf (stderr,"No MIP objective value available. Exiting...\n");
goto TERMINATE;
}
printf ("Solution value (maximum profit) = %f\n\n", objval);
colcnt = NUMVARS*NUMMONTHS*NUMPRODUCTS;
x = malloc (colcnt * sizeof(*x));
if ( x == NULL ) {
status = CPXERR_NO_MEMORY;
fprintf (stderr, "Could not allocate memory for solution.\n");
goto TERMINATE;
}
status = CPXXgetx (env, lp, x, 0, colcnt - 1);
if ( status ) {
fprintf (stderr, "Failed to get optimal integer x.\n");
goto TERMINATE;
}
for (m = 0; m < NUMMONTHS; m++) {
printf ("Month %d \n", m);
printf (" . buy ");
for (p = 0; p < NUMPRODUCTS; p++)
printf ("%f\t", x[varindex(m, p, BUY)]);
printf ("\n");
printf (" . use ");
for (p = 0; p < NUMPRODUCTS; p++)
printf ("%f\t", x[varindex (m, p, USE)]);
printf ("\n");
printf (" . store ");
for (p = 0; p < NUMPRODUCTS; p++)
printf ("%f\t", x[varindex (m, p, STORE)]);
printf ("\n");
}
/* Free problem */
status = CPXXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXXfreeprob failed, error code %d.\n", status);
goto TERMINATE;
}
TERMINATE:
free_and_null ((char **) &x);
/* Free up the problem as allocated by CPXXcreateprob, if necessary */
if ( lp != NULL ) {
status = CPXXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXXfreeprob failed, error code %d.\n", status);
}
}
/* Free up the CPLEX environment, if necessary */
if ( env != NULL ) {
status = CPXXcloseCPLEX (&env);
/* Note that CPXXcloseCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( status ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not close CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
}
}
return (status);
} /* END main */
int
main (void)
{
/* Declare pointers for the variables and arrays that will contain
the data which define the LP problem. The setproblemdata() routine
allocates space for the problem data. */
char *probname = NULL;
CPXDIM numcols;
CPXDIM numrows;
int objsen;
double *obj = NULL;
double *rhs = NULL;
char *sense = NULL;
CPXNNZ *matbeg = NULL;
CPXDIM *matcnt = NULL;
CPXDIM *matind = NULL;
double *matval = NULL;
double *lb = NULL;
double *ub = NULL;
CPXNNZ *qmatbeg = NULL;
CPXDIM *qmatcnt = NULL;
CPXDIM *qmatind = NULL;
double *qmatval = NULL;
/* Declare pointers for the variables that will contain the data
for the constraint that cuts off certain local optima. */
CPXDIM numrows_extra;
CPXNNZ numnnz_extra;
double *rhs_extra = NULL;
char *sense_extra = NULL;
CPXNNZ *rmatbeg = NULL;
CPXDIM *rmatind = NULL;
double *rmatval = NULL;
CPXDIM rowind[1];
/* Declare and allocate space for the variables and arrays where we
will store the optimization results including the status, objective
value, variable values, dual values, row slacks and variable
reduced costs. */
int solstat;
double objval;
CPXENVptr env = NULL;
CPXLPptr lp = NULL;
int status;
/* Initialize the CPLEX environment */
env = CPXXopenCPLEX (&status);
/* If an error occurs, the status value indicates the reason for
failure. A call to CPXXgeterrorstring will produce the text of
the error message. Note that CPXXopenCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( env == NULL ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not open CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
goto TERMINATE;
}
/* Turn on output to the screen */
status = CPXXsetintparam (env, CPXPARAM_ScreenOutput, CPX_ON);
if ( status ) {
fprintf (stderr,
"Failure to turn on screen indicator, error %d.\n", status);
goto TERMINATE;
}
/* Fill in the data for the problem. */
status = setproblemdata (&probname, &numcols, &numrows, &objsen, &obj,
&rhs, &sense, &matbeg, &matcnt, &matind,
&matval, &lb, &ub, &qmatbeg, &qmatcnt,
&qmatind, &qmatval,
&numrows_extra, &numnnz_extra,
&rhs_extra, &sense_extra,
&rmatbeg, &rmatind, &rmatval);
if ( status ) {
fprintf (stderr, "Failed to build problem data arrays.\n");
goto TERMINATE;
}
/* Create the problem. */
lp = CPXXcreateprob (env, &status, probname);
/* 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 CPXPARAM_ScreenOutput causes the error message to
appear on stdout. */
if ( lp == NULL ) {
fprintf (stderr, "Failed to create problem.\n");
goto TERMINATE;
}
/* Now copy the LP part of the problem data into the lp */
status = CPXXcopylp (env, lp, numcols, numrows, objsen, obj, rhs,
sense, matbeg, matcnt, matind, matval,
lb, ub, NULL);
if ( status ) {
fprintf (stderr, "Failed to copy problem data.\n");
goto TERMINATE;
}
status = CPXXcopyquad (env, lp, qmatbeg, qmatcnt, qmatind, qmatval);
if ( status ) {
fprintf (stderr, "Failed to copy quadratic matrix.\n");
goto TERMINATE;
}
/* When a non-convex objective function is present, CPLEX will
return error CPXERR_Q_NOT_POS_DEF unless the parameter
CPXPARAM_SolutionTarget is set to accept first-order optimal
solutions. */
status = CPXXsetintparam (env, CPXPARAM_SolutionTarget, CPX_SOLUTIONTARGET_FIRSTORDER);
if ( status ) goto TERMINATE;
/* Optimize the problem and obtain solution. */
status = optimize_and_report(env, lp, &solstat, &objval);
if ( status ) goto TERMINATE;
/* Add a constraint to cut off the solution at (-1, 1) */
status = CPXXaddrows (env, lp, 0, numrows_extra, numnnz_extra,
rhs_extra, sense_extra,
rmatbeg, rmatind, rmatval,
NULL, NULL);
if ( status ) goto TERMINATE;
status = optimize_and_report(env, lp, &solstat, &objval);
if ( status ) goto TERMINATE;
/* Reverse the sense of the new constraint to cut off the solution at (1, 1) */
rowind[0] = CPXXgetnumrows (env, lp) - 1;
status = CPXXchgsense (env, lp, 1, rowind, "L");
if ( status ) goto TERMINATE;
status = optimize_and_report(env, lp, &solstat, &objval);
if ( status ) goto TERMINATE;
/* Finally, write a copy of the problem to a file. */
status = CPXXwriteprob (env, lp, "indefqpex1.lp", NULL);
if ( status ) {
fprintf (stderr, "Failed to write LP to disk.\n");
goto TERMINATE;
}
TERMINATE:
/* Free up the problem as allocated by CPXXcreateprob, if necessary */
if ( lp != NULL ) {
status = CPXXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXXfreeprob failed, error code %d.\n", status);
}
}
/* Free up the CPLEX environment, if necessary */
if ( env != NULL ) {
status = CPXXcloseCPLEX (&env);
/* Note that CPXXcloseCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( status ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not close CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
}
}
/* Free up the problem data arrays, if necessary. */
free_and_null ((char **) &probname);
free_and_null ((char **) &obj);
free_and_null ((char **) &rhs);
free_and_null ((char **) &sense);
free_and_null ((char **) &matbeg);
free_and_null ((char **) &matcnt);
free_and_null ((char **) &matind);
free_and_null ((char **) &matval);
free_and_null ((char **) &lb);
free_and_null ((char **) &ub);
free_and_null ((char **) &qmatbeg);
free_and_null ((char **) &qmatcnt);
free_and_null ((char **) &qmatind);
free_and_null ((char **) &qmatval);
free_and_null ((char **) &rhs_extra);
free_and_null ((char **) &sense_extra);
free_and_null ((char **) &rmatbeg);
free_and_null ((char **) &rmatind);
free_and_null ((char **) &rmatval);
return (status);
} /* END main */
int
main (void)
{
char probname[16]; /* Problem name is max 16 characters */
/* Declare and allocate space for the variables and arrays where we
will store the optimization results including the status, objective
value, variable values, dual values, row slacks and variable
reduced costs. */
int solstat;
double objval;
double x[NUMCOLS];
double pi[NUMROWS];
double slack[NUMROWS];
double dj[NUMCOLS];
CPXENVptr env = NULL;
CPXLPptr lp = NULL;
int status;
CPXDIM i, j;
CPXDIM cur_numrows, cur_numcols;
char errmsg[CPXMESSAGEBUFSIZE];
CPXCHANNELptr cpxerror = NULL;
CPXCHANNELptr cpxwarning = NULL;
CPXCHANNELptr cpxresults = NULL;
CPXCHANNELptr ourchannel = NULL;
char *errorlabel = "cpxerror";
char *warnlabel = "cpxwarning";
char *reslabel = "cpxresults";
char *ourlabel = "Our Channel";
CPXFILEptr fpout = NULL;
/* Initialize the CPLEX environment */
env = CPXXopenCPLEX (&status);
/* If an error occurs, the status value indicates the reason for
failure. A call to CPXXgeterrorstring will produce the text of
the error message. Note that CPXXopenCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
/* Since the message handler is yet to be set up, we'll call our
messaging function directly to print out any errors */
if ( env == NULL ) {
ourmsgfunc ("Our Message", "Could not open CPLEX environment.\n");
goto TERMINATE;
}
/* Now get the standard channels. If an error, just call our
message function directly. */
status = CPXXgetchannels (env, &cpxresults, &cpxwarning, &cpxerror, NULL);
if ( status ) {
ourmsgfunc ("Our Message", "Could not get standard channels.\n");
CPXXgeterrorstring (env, status, errmsg);
ourmsgfunc ("Our Message", errmsg);
goto TERMINATE;
}
/* Now set up the error channel first. The label will be "cpxerror" */
status = CPXXaddfuncdest (env, cpxerror, errorlabel, ourmsgfunc);
if ( status ) {
ourmsgfunc ("Our Message", "Could not set up error message handler.\n");
CPXXgeterrorstring (env, status, errmsg);
ourmsgfunc ("Our Message", errmsg);
}
/* Now that we have the error message handler set up, all CPLEX
generated errors will go through ourmsgfunc. So we don't have
to use CPXXgeterrorstring to determine the text of the message.
We can also use CPXXmsg to do any other printing. */
status = CPXXaddfuncdest (env, cpxwarning, warnlabel, ourmsgfunc);
if ( status ) {
CPXXmsg (cpxerror, "Failed to set up handler for cpxwarning.\n");
goto TERMINATE;
}
status = CPXXaddfuncdest (env, cpxresults, reslabel, ourmsgfunc);
if ( status ) {
CPXXmsg (cpxerror, "Failed to set up handler for cpxresults.\n");
goto TERMINATE;
}
/* Now turn on the iteration display. */
status = CPXXsetintparam (env, CPXPARAM_Simplex_Display, 2);
if ( status ) {
CPXXmsg (cpxerror, "Failed to turn on simplex display level.\n");
goto TERMINATE;
}
/* Create the problem. */
strcpy (probname, "example");
lp = CPXXcreateprob (env, &status, probname);
/* 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 CPXPARAM_ScreenOutput causes the error message to
appear on stdout. */
if ( lp == NULL ) {
CPXXmsg (cpxerror, "Failed to create LP.\n");
goto TERMINATE;
}
/* Now populate the problem with the data. */
status = populatebycolumn (env, lp);
if ( status ) {
CPXXmsg (cpxerror, "Failed to populate problem data.\n");
goto TERMINATE;
}
/* Optimize the problem and obtain solution. */
status = CPXXlpopt (env, lp);
if ( status ) {
CPXXmsg (cpxerror, "Failed to optimize LP.\n");
goto TERMINATE;
}
status = CPXXsolution (env, lp, &solstat, &objval, x, pi, slack, dj);
if ( status ) {
CPXXmsg (cpxerror, "Failed to obtain solution.\n");
goto TERMINATE;
}
/* Write the output to the screen. We will also write it to a
file as well by setting up a file destination and a function
destination. */
ourchannel = CPXXaddchannel (env);
if ( ourchannel == NULL ) {
CPXXmsg (cpxerror, "Failed to set up our private channel.\n");
goto TERMINATE;
}
fpout = CPXXfopen ("lpex5.msg", "w");
if ( fpout == NULL ) {
CPXXmsg (cpxerror, "Failed to open lpex5.msg file for output.\n");
goto TERMINATE;
}
status = CPXXaddfpdest (env, ourchannel, fpout);
if ( status ) {
CPXXmsg (cpxerror, "Failed to set up output file destination.\n");
goto TERMINATE;
}
status = CPXXaddfuncdest (env, ourchannel, ourlabel, ourmsgfunc);
if ( status ) {
CPXXmsg (cpxerror, "Failed to set up our output function.\n");
goto TERMINATE;
}
/* Now any message to channel ourchannel will go into the file
and into the file opened above. */
CPXXmsg (ourchannel, "\nSolution status = %d\n", solstat);
CPXXmsg (ourchannel, "Solution value = %f\n\n", objval);
/* The size of the problem should be obtained by asking CPLEX what
the actual size is, rather than using sizes from when the problem
was built. cur_numrows and cur_numcols store the current number
of rows and columns, respectively. */
cur_numrows = CPXXgetnumrows (env, lp);
cur_numcols = CPXXgetnumcols (env, lp);
for (i = 0; i < cur_numrows; i++) {
CPXXmsg (ourchannel, "Row %d: Slack = %10f Pi = %10f\n",
i, slack[i], pi[i]);
}
for (j = 0; j < cur_numcols; j++) {
CPXXmsg (ourchannel, "Column %d: Value = %10f Reduced cost = %10f\n",
j, x[j], dj[j]);
}
/* Finally, write a copy of the problem to a file. */
status = CPXXwriteprob (env, lp, "lpex5.lp", NULL);
if ( status ) {
CPXXmsg (cpxerror, "Failed to write LP to disk.\n");
goto TERMINATE;
}
TERMINATE:
/* First check if ourchannel is open */
if ( ourchannel != NULL ) {
int chanstat;
chanstat = CPXXdelfuncdest (env, ourchannel, ourlabel, ourmsgfunc);
if ( chanstat ) {
strcpy (errmsg, "CPXXdelfuncdest failed.\n");
ourmsgfunc ("Our Message", errmsg);
if (!status) status = chanstat;
}
if ( fpout != NULL ) {
chanstat = CPXXdelfpdest (env, ourchannel, fpout);
if ( chanstat ) {
strcpy (errmsg, "CPXXdelfpdest failed.\n");
ourmsgfunc ("Our Message", errmsg);
if (!status) status = chanstat;
}
CPXXfclose (fpout);
}
chanstat = CPXXdelchannel (env, &ourchannel);
if ( chanstat ) {
strcpy (errmsg, "CPXXdelchannel failed.\n");
ourmsgfunc ("Our Message", errmsg);
if (!status) status = chanstat;
}
}
/* Free up the problem as allocated by CPXXcreateprob, if necessary */
if ( lp != NULL ) {
status = CPXXfreeprob (env, &lp);
if ( status ) {
strcpy (errmsg, "CPXXfreeprob failed.\n");
ourmsgfunc ("Our Message", errmsg);
}
}
/* Now delete our function destinations from the 3 CPLEX channels. */
if ( cpxresults != NULL ) {
int chanstat;
chanstat = CPXXdelfuncdest (env, cpxresults, reslabel, ourmsgfunc);
if ( chanstat && !status ) {
status = chanstat;
strcpy (errmsg, "Failed to delete cpxresults function.\n");
ourmsgfunc ("Our Message", errmsg);
}
}
if ( cpxwarning != NULL ) {
int chanstat;
chanstat = CPXXdelfuncdest (env, cpxwarning, warnlabel, ourmsgfunc);
if ( chanstat && !status ) {
status = chanstat;
strcpy (errmsg, "Failed to delete cpxwarning function.\n");
ourmsgfunc ("Our Message", errmsg);
}
}
if ( cpxerror != NULL ) {
int chanstat;
chanstat = CPXXdelfuncdest (env, cpxerror, errorlabel, ourmsgfunc);
if ( chanstat && !status ) {
status = chanstat;
strcpy (errmsg, "Failed to delete cpxerror function.\n");
ourmsgfunc ("Our Message", errmsg);
}
}
/* Free up the CPLEX environment, if necessary */
if ( env != NULL ) {
status = CPXXcloseCPLEX (&env);
/* Note that CPXXcloseCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( status ) {
strcpy (errmsg, "Could not close CPLEX environment.\n");
ourmsgfunc ("Our Message", errmsg);
CPXXgeterrorstring (env, status, errmsg);
ourmsgfunc ("Our Message", errmsg);
}
}
return (status);
} /* END main */
int
main (void)
{
/* Declare variables and arrays where we will store the
optimization results including the status, objective value,
and variable values. */
int solstat;
double objval;
double x[2*NUMEDGES]; /* One flow variable and one fixed charge indicator
for each edge */
CPXENVptr env = NULL;
CPXLPptr lp = NULL;
int status;
int j;
/* Initialize the CPLEX environment */
env = CPXXopenCPLEX (&status);
/* If an error occurs, the status value indicates the reason for
failure. A call to CPXXgeterrorstring will produce the text of
the error message. Note that CPXXopenCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( env == NULL ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not open CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
goto TERMINATE;
}
/* Turn on output to the screen */
status = CPXXsetintparam (env, CPXPARAM_ScreenOutput, CPX_ON);
if ( status ) {
fprintf (stderr,
"Failure to turn on screen indicator, error %d.\n", status);
goto TERMINATE;
}
/* Create the problem. */
lp = CPXXcreateprob (env, &status, "fixnet");
/* 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 CPXPARAM_ScreenOutput causes the error message to
appear on stdout. */
if ( lp == NULL ) {
fprintf (stderr, "Failed to create LP.\n");
goto TERMINATE;
}
/* Build the fixed-charge network flow model using
indicator constraints. */
status = buildnetwork (env, lp);
if ( status ) {
fprintf (stderr, "Failed to build network.\n");
goto TERMINATE;
}
/* Optimize the problem and obtain solution. */
status = CPXXmipopt (env, lp);
if ( status ) {
fprintf (stderr, "Failed to optimize MIP.\n");
goto TERMINATE;
}
solstat = CPXXgetstat (env, lp);
/* Write solution status and objective to the screen. */
printf ("\nSolution status = %d\n", solstat);
status = CPXXgetobjval (env, lp, &objval);
if ( status ) {
fprintf (stderr, "No MIP objective value available. Exiting...\n");
goto TERMINATE;
}
printf ("Solution value = %f\n", objval);
printf ("Solution vector:\n");
dumpx (env, lp);
status = CPXXgetx (env, lp, x, 0, 2*NUMEDGES-1);
if ( status ) {
fprintf (stderr, "Failed to get optimal integer x.\n");
goto TERMINATE;
}
/* Make sure flow satisfies fixed-charge constraints */
for (j = 0; j < NUMEDGES; j++) {
if ( x[j] > 0.0001 && x[NUMEDGES+j] < 0.9999 ) {
printf ("WARNING : Edge from %d to %d has non-zero flow %.3f\n",
orig[j], dest[j], x[j]);
printf (" : fixed-charge indicator has value %.6f.\n",
x[NUMEDGES+j]);
}
}
printf("\n");
/* Finally, write a copy of the problem to a file. */
status = CPXXwriteprob (env, lp, "fixnet.lp", NULL);
if ( status ) {
fprintf (stderr, "Failed to write LP to disk.\n");
goto TERMINATE;
}
/* Free problem */
status = CPXXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXXfreeprob failed, error code %d.\n", status);
goto TERMINATE;
}
TERMINATE:
/* Free up the problem as allocated by CPXXcreateprob, if necessary */
if ( lp != NULL ) {
status = CPXXfreeprob (env, &lp);
if ( status ) {
fprintf (stderr, "CPXXfreeprob failed, error code %d.\n", status);
}
}
/* Free up the CPLEX environment, if necessary */
if ( env != NULL ) {
status = CPXXcloseCPLEX (&env);
/* Note that CPXXcloseCPLEX produces no output,
so the only way to see the cause of the error is to use
CPXXgeterrorstring. For other CPLEX routines, the errors will
be seen if the CPXPARAM_ScreenOutput indicator is set to CPX_ON. */
if ( status ) {
char errmsg[CPXMESSAGEBUFSIZE];
fprintf (stderr, "Could not close CPLEX environment.\n");
CPXXgeterrorstring (env, status, errmsg);
fprintf (stderr, "%s", errmsg);
}
}
return (status);
} /* END main */
