static int
populatebycolumn (CPXENVptr env, CPXLPptr lp)
{
int status = 0;
double obj[NUMCOLS];
double lb[NUMCOLS];
double ub[NUMCOLS];
char const *colname[NUMCOLS];
CPXNNZ matbeg[NUMCOLS];
CPXDIM matind[NUMNZ];
double matval[NUMNZ];
double rhs[NUMROWS];
char sense[NUMROWS];
char const *rowname[NUMROWS];
/* To build the problem by column, create the rows, and then
add the columns. */
status = CPXXchgobjsen (env, lp, CPX_MAX); /* Problem is maximization */
if ( status ) goto TERMINATE;
/* Now create the new rows. First, populate the arrays. */
rowname[0] = "c1";
sense[0] = 'L';
rhs[0] = 20.0;
rowname[1] = "c2";
sense[1] = 'L';
rhs[1] = 30.0;
status = CPXXnewrows (env, lp, NUMROWS, rhs, sense, NULL, rowname);
if ( status ) goto TERMINATE;
/* Now add the new columns. First, populate the arrays. */
obj[0] = 1.0; obj[1] = 2.0; obj[2] = 3.0;
matbeg[0] = 0; matbeg[1] = 2; matbeg[2] = 4;
matind[0] = 0; matind[2] = 0; matind[4] = 0;
matval[0] = -1.0; matval[2] = 1.0; matval[4] = 1.0;
matind[1] = 1; matind[3] = 1; matind[5] = 1;
matval[1] = 1.0; matval[3] = -3.0; matval[5] = 1.0;
lb[0] = 0.0; lb[1] = 0.0; lb[2] = 0.0;
ub[0] = 40.0; ub[1] = CPX_INFBOUND; ub[2] = CPX_INFBOUND;
colname[0] = "x1"; colname[1] = "x2"; colname[2] = "x3";
status = CPXXaddcols (env, lp, NUMCOLS, NUMNZ, obj, matbeg, matind,
matval, lb, ub, colname);
if ( status ) goto TERMINATE;
TERMINATE:
return (status);
} /* END populatebycolumn */
static int
buildnetwork (CPXENVptr env, CPXLPptr lp)
{
char sense[NUMNODES];
double rhs[NUMNODES];
CPXDIM ind[2];
double val[2];
char const *name[1];
char buffer[100];
int i, j;
CPXDIM varindex;
CPXNNZ zero = 0;
double dblzero = 0.0;
double dblone = 1.0;
char binary = 'B';
int status = 0;
/* Create constraint placeholders ---
One constraint for each node (flow constraints)
*/
for (i = 0; i < NUMNODES; i++) {
rhs[i] = demand[i];
sense[i] = 'G';
}
status = CPXXnewrows (env, lp, NUMNODES, rhs, sense, NULL, NULL);
if ( status ) {
fprintf (stderr, "Could not create new rows.\n");
goto TERMINATE;
}
/* Add flow variables */
for (j = 0; j < NUMEDGES; j++) {
ind[0] = orig[j]; /* Flow leaves origin */
val[0] = -1.0;
ind[1] = dest[j]; /* Flow arrives at destination */
val[1] = 1.0;
name[0] = buffer;
sprintf(buffer, "x%d%d", orig[j], dest[j]);
status = CPXXaddcols (env, lp, 1, 2, &unitcost[j], &zero, ind, val,
NULL, NULL, name);
if ( status ) {
fprintf (stderr, "Failed to add flow edge.\n");
goto TERMINATE;
}
}
/* Add fixed charge variables */
for (j = 0; j < NUMEDGES; j++) {
name[0] = buffer;
sprintf(buffer, "f%d%d", orig[j], dest[j]);
status = CPXXaddcols (env, lp, 1, 0, &fixedcost[j], &zero, ind, val,
&dblzero, &dblone, name);
if ( status ) {
fprintf (stderr, "Failed to add fixed charge variable.\n");
goto TERMINATE;
}
varindex = NUMEDGES+j;
status = CPXXchgctype (env, lp, 1, &varindex, &binary);
if ( status ) {
fprintf (stderr, "Failed to change variable type.\n");
goto TERMINATE;
}
}
/* Add indicator constraints --
f = 0 -> x <= 0 */
for (j = 0; j < NUMEDGES; j++) {
varindex = j;
sprintf(buffer, "indicator%d", j);
status = CPXXaddindconstr (env, lp, NUMEDGES+j, 1, 1,
0.0, 'L', &varindex, &dblone, buffer);
if ( status ) {
fprintf (stderr, "Failed to add indicator constraint.");
goto TERMINATE;
}
}
TERMINATE:
return (status);
} /* END buildnetwork */
static int
colsteel (int numprod, int tweeks, double const *rate,
double const *inv0, double const *avail, double const *flatmarket,
double const *prodcost, double const *invcost,
double const *flatrevenue, CPXENVptr env, CPXLPptr lp)
{
double *obj = NULL;
char *sense = NULL;
CPXNNZ *cmatbeg = NULL;
CPXDIM *cmatind = NULL;
double *cmatval = NULL;
double *lb = NULL;
double *ub = NULL;
CPXCHANNELptr cpxerror = NULL;
int t,p; /* Various loop counters */
CPXNNZ k;
int status = 0;
printf ("Building model by column.\n");
status = CPXXgetchannels (env, NULL, NULL, &cpxerror, NULL);
if ( status ) goto TERMINATE;
/* Set the objective sense to be maximize */
status = CPXXchgobjsen (env, lp, CPX_MAX);
if ( status ) {
CPXXmsg (cpxerror, "Could not change objective sense. Error %d\n",
status);
goto TERMINATE;
}
/* Set up the constraints for the problem */
/* First do the time constraints. Allocate space for a sense array. */
sense = malloc (tweeks*sizeof(*sense));
if ( sense == NULL ) {
status = -2;
goto TERMINATE;
}
for (t = 0; t < tweeks; t++) {
sense[t] = 'L';
}
status = CPXXnewrows (env, lp, tweeks, avail, sense, NULL, NULL);
if ( status ) {
CPXXmsg (cpxerror,
"CPXXnewrows failed to add time constraints. Error %d\n",
status);
goto TERMINATE;
}
/* Free up the temporary sense array */
free (sense); sense = NULL;
/* Now do the balance constraints.
Can do this without temporary arrays, because the only nonzero
is the negative of the inventory levels. */
for (p = 0; p < numprod; p++) {
double temprhs = -inv0[p];
/* Fill in the initial inventory level */
status = CPXXnewrows (env, lp, 1, &temprhs, NULL, NULL, NULL);
if ( status ) {
CPXXmsg (cpxerror, "%sfor product %d. Error %d.\n",
"CPXXnewrows failed to add initial inventory constraint\n",
p, status);
goto TERMINATE;
}
/* The remaining balance constraints have 0.0 as the rhs value,
and are equality constraints. No need to specify the arrays */
status = CPXXnewrows (env, lp, tweeks-1, NULL, NULL, NULL, NULL);
if ( status ) {
CPXXmsg (cpxerror, "%sfor product %d. Error %d.\n",
"CPXXnewrows failed to add other inventory constraints\n",
p, status);
goto TERMINATE;
}
}
/* Now, add the variables. For each set of variables, we allocate
* arrays to hold the data for the CPXXaddcols() calls, and then free
* them up, so that each set of variables is maintained in a "local"
* piece of code.
*/
/* First, do the Make variables. Each Make[p][t] variable has
* objective coefficient -prodcost[p], and bounds of (0, +infinity).
* Each Make[p][t] variable appears in the constraints
* time(t) and balance(p,t).
* Create temporary arrays to hold the objective coefficients,
* lower and upper bounds, and matrix coefficients for one product.
*/
obj = malloc (tweeks*sizeof(*obj));
cmatbeg = malloc (tweeks*sizeof(*cmatbeg));
cmatind = malloc (2*tweeks*sizeof(*cmatind));
cmatval = malloc (2*tweeks*sizeof(*cmatval));
if ( obj == NULL ||
cmatbeg == NULL ||
cmatind == NULL ||
cmatval == NULL ) {
status = -2;
goto TERMINATE;
}
for (p = 0; p < numprod; p++) {
k = 0; /* Reset the nonzero count for each product */
for (t = 0; t < tweeks; t++) {
cmatbeg[t] = k;
obj[t] = -prodcost[p];
cmatind[k] = t;
cmatval[k] = 1.0/rate[p];
k++;
cmatind[k] = (p + 1)*tweeks + t;
cmatval[k] = 1.0;
k++;
}
status = CPXXaddcols (env, lp, tweeks, k, obj, cmatbeg, cmatind,
cmatval, NULL, NULL, NULL);
if ( status ) {
CPXXmsg (cpxerror, "%sfor product %d. Error %d.\n",
"CPXXaddcols failed to add Make variables\n",
p, status);
goto TERMINATE;
}
}
/* Free up allocated memory used to add Make variables */
free (obj); obj = NULL;
free (cmatbeg); cmatbeg = NULL;
free (cmatind); cmatind = NULL;
free (cmatval); cmatval = NULL;
/* Now do the Inv variables in (p,t) order. Each Inv[p][t] variable
* has objective coefficient -invcost[p], and bounds of (0, +infinity).
* If t is not tweeks-1, then Inv[p][t] appears in constraints
* balance(p,t) and balance(p,t+1).
* If t is tweeks-1, then Inv[p][t] appears only in
* constraint balance(p,t).
* Create temporary arrays to hold the objective coefficients,
* lower and upper bounds, and matrix coefficients for one product.
*/
obj = malloc (tweeks*sizeof(*obj));
cmatbeg = malloc (tweeks*sizeof(*cmatbeg));
cmatind = malloc (2*tweeks*sizeof(*cmatind));
cmatval = malloc (2*tweeks*sizeof(*cmatval));
if ( obj == NULL ||
cmatbeg == NULL ||
cmatind == NULL ||
cmatval == NULL ) {
status = -2;
goto TERMINATE;
}
for (p = 0; p < numprod; p++) {
k = 0; /* Reset the nonzero count for each product */
for (t = 0; t < tweeks; t++) {
obj[t] = -invcost[p];
cmatbeg[t] = k;
cmatind[k] = (p+1)*tweeks + t;
cmatval[k] = -1.0;
k++;
cmatind[k] = (p+1)*tweeks + t+1;
cmatval[k] = 1.0;
k++;
}
/* Now repair the coefficient for t=tweeks-1 by passing k-1 as
* the number of nonzeros, so that the last coefficient is
* ignored.
*/
status = CPXXaddcols (env, lp, tweeks, k-1, obj, cmatbeg, cmatind,
cmatval, NULL, NULL, NULL);
if ( status ) {
CPXXmsg (cpxerror, "%sfor product %d. Error %d.\n",
"CPXXaddcols failed to add Inv variables\n",
p, status);
goto TERMINATE;
}
}
/* Free up allocated memory used to add Inv variables */
free (obj); obj = NULL;
free (cmatbeg); cmatbeg = NULL;
free (cmatind); cmatind = NULL;
free (cmatval); cmatval = NULL;
/* Now do the Sell[p][t] variables. The objective coefficients of
* Sell[p][t] is flatrevenue[p*tweeks+t], which means that
* we can pull the objective coefficients from the slice of that
* array. The lower bounds are 0.0, and the upper bounds are
* flatmarket[p*tweeks+t], which means that we can pull the
* upper bounds from the slice of that array. Each Sell variable
* appears only in the balance(p,t) constraint.
* Create temporary arrays to hold the bounds, and matrix
* coefficients for one product.
*/
cmatbeg = malloc (tweeks*sizeof(*cmatbeg));
cmatind = malloc (tweeks*sizeof(*cmatind));
cmatval = malloc (tweeks*sizeof(*cmatval));
if ( cmatbeg == NULL ||
cmatind == NULL ||
cmatval == NULL ) {
status = -2;
goto TERMINATE;
}
for (p = 0; p < numprod; p++) {
k = 0; /* Reset the nonzero count for each product */
for (t = 0; t < tweeks; t++) {
cmatbeg[t] = k;
cmatind[k] = (p+1)*tweeks + t;
cmatval[k] = -1.0;
k++;
}
status = CPXXaddcols (env, lp, tweeks, k, &flatrevenue[p*tweeks],
cmatbeg, cmatind, cmatval, NULL,
&flatmarket[p*tweeks], NULL);
if ( status ) {
CPXXmsg (cpxerror, "%sfor product %d. Error %d.\n",
"CPXXaddcols failed to add Sell variables\n",
p, status);
goto TERMINATE;
}
}
/* Free up allocated memory used to add Sell variables */
free (lb); lb = NULL;
free (cmatbeg); cmatbeg = NULL;
free (cmatind); cmatind = NULL;
free (cmatval); cmatval = NULL;
TERMINATE:
if ( obj != NULL ) free ( obj );
if ( sense != NULL ) free ( sense );
if ( cmatbeg != NULL ) free ( cmatbeg );
if ( cmatind != NULL ) free ( cmatind );
if ( cmatval != NULL ) free ( cmatval );
if ( lb != NULL ) free ( lb );
if ( ub != NULL ) free ( ub );
return (status);
} /* END colsteel */
