/******************************************************** BCL Example Problems ==================== file xbdlvriis.c ```````````````` Transportation problem (infeasible data). Retrieving and printing IIS. (c) 2008 Fair Isaac Corporation author: S.Heipcke, 2005, rev. Mar. 2011 ********************************************************/ #include <stdio.h>
#include <stdlib.h>
#include "xprb.h"

#define NSupp 10                        /* Number of suppliers */
#define NCust 7                         /* Number of customers */
#define MaxArcs 100                     /* Max. num. of non-zero cost values */

#define VANFILE XPRBDATAPATH "/delivery/ifvan.dat"    /* Van data file */
#define COSTFILE XPRBDATAPATH "/delivery/cost.dat"    /* Cost data file */

/****DATA****/
/* Supplier:      London  Luton  B'ham Bristl  Derby Stckpt   York */
double SUPPLY[] = {140.0, 200.0,  50.0,  10.0, 400.0, 200.0,  20.0,
/* Supplier: Derby  Soton Scnthp */
             90.0,  30.0,  12};
/* Customer:       London Livpol Doncst   York   Hull  Manchr Shffld */
double DEMAND[] = {1230.3, 560.4, 117.1, 592.8, 310.0, 1247.0,  86};

double COST[NSupp][NCust];        /* Cost per supplier-customer pair */

double IFVAN[NSupp][NCust];       /* Non-zero if route uses vans instead
                                     of lorries */
double VANCAP=40;               /* Capacity on routes that use vans */

/***********************************************************************/

void moddelivery(XPRBprob prob)
{
 XPRBctr ctr;
 int s,c,i;
 XPRBvar x[NSupp][NCust];
 XPRBctr *iisctr;
 XPRBvar *iisvar;
 int numv, numc, numiis, ct;

/****VARIABLES****/
 for(s=0;s<NSupp;s++) for(c=0; x[s][c]=XPRBnewvar(prob,XPRB_PL,XPRBnewname("x_s%d",s), ctr=XPRBnewctr(prob,"OBJ",XPRB_N); for(s=0;s<NSupp;s++) Objective: Minimize total cost Set objective function Satisfy demand of each customer Keep within supply at if(IFVAN[s][c]!=0) sense to minimization Solve the LP-problem status: if (XPRBgetlpstat(prob)==XPRB_LP_OPTIMAL) Get value else IIS numiis=XPRBgetnumiis(prob); number independent IIS:>0)
   {                              /* Print all variables in the IIS */
    printf("        Variables: ");
    for(i=0;i<numv;i++) printf(%s=", XPRBgetvarname(iisvar[i]));
    printf(" Free the array of variables if>0)
   {                              /* Print all constraints in the IIS */
    printf("        Constraints: ");
    for(i=0;i<numc;i++) printf(%s=", XPRBgetctrname(iisctr[i]));
    printf(" Free the array of constraints Alternative way enumerating IIS: approximation: with non-zero reduced ct=0;>0)
  {
   if(ct>0)
    printf("IIS %d:  %d variables, %d constraints\n", ct, numv, numc);
   ct++;
   XPRBgetiis(prob, NULL, &numv, NULL, &numc, ct);
  }

/* Retrieve variables only */
  for(s=1;s<=numiis;s++)
  {
   XPRBgetiis(prob, &iisvar, &numv, NULL, NULL, s);
   printf("IIS %d:  %d variables ( ", s, numv);
   if (numv>0)
   {
    for(i=0;i<numv;i++) printf(%s=", XPRBgetvarname(iisvar[i]));
    XPRBfreemem(iisvar);          /* Free the array of variables */
   }
   printf(" Retrieve constraints only for(s=1;s<=numiis;s++)>0)
   {
    for(i=0;i<numc;i++) printf("%s ", XPRBgetctrname(iisctr[i]));
    XPRBfreemem(iisctr);          /* Free the array of constraints */
   }
   printf(")\n");
  }

 }

}

/***********************************************************************/

    /**** Read data from files ****/
void readdata(void)
{
 FILE *datafile;
 int s,c;

        /* Initialize data tables to 0 */
 for(s=0;s<NSupp;s++)
  for(c=0; c<NCust; c++)
  {
   COST[s][c] = 0;
   IFVAN[s][c] = 0;
  }
        /* Read the demand data file */
 datafile=fopen(COSTFILE,"r");
 for(s=0;s<NSupp;s++)
  XPRBreadarrlinecb(XPRB_FGETS, datafile, 99, "g,", COST[s], NCust);
 fclose(datafile);

        /* Read the van data file */
 datafile=fopen(VANFILE,"r");
 for(s=0;s<NSupp;s++)
  XPRBreadarrlinecb(XPRB_FGETS, datafile, 99, "g,", IFVAN[s], NCust);
 fclose(datafile);
}

/***********************************************************************/

int main(int argc, char **argv)
{
 XPRBprob prob;

 prob=XPRBnewprob("Delivery");   /* Initialize a new problem in BCL */
 readdata();                     /* Data input from file */
 moddelivery(prob);              /* Problem formulation & solving */

 return 0;
}