/********************************************************
  BCL Example Problems
  ====================

  file xbdelivr.c
  ```````````````
  Transportation problem.
  Use of arrays.

  (c) 2008-2024 Fair Isaac Corporation
      author: S.Heipcke, Jan. 2000, rev. Mar. 2011
********************************************************/

#include <stdio.h>
#include "xprb.h"

/* define or undefine ARRAY in order to switch between model formulations
   with or without variable arrays in constraint definition */
#define ARRAY

#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, 600.0,  50.0,  10.0, 400.0, 200.0,  20.0,
/* Supplier: Derby  Soton Scnthp */
             90.0,  30.0,  12.0};
/* Customer:      London Livpol Doncst   York   Hull Manchr Shffld */
double DEMAND[] = {123.3,  56.4,  17.1, 192.8, 310.0,  47.0,  86.0};

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

double IFVAN[NSupp][NCust];       /* Non-zero if route uses vans instead
                                     of lorries */
double VANCAP=40.0;               /* Capacity on routes that use vans */

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

void moddelivery(XPRBprob prob)
{
 XPRBctr ctr;
 int s,c;
 XPRBvar x[NSupp][NCust];

/****VARIABLES****/
 for(s=0;s<NSupp;s++)
  for(c=0; c<NCust; c++)
   x[s][c]=XPRBnewvar(prob,XPRB_PL,XPRBnewname("x_s%d",s), 0, XPRB_INFINITY);

/****OBJECTIVE****/
 ctr = XPRBnewctr(prob,"OBJ",XPRB_N);
 for(s=0;s<NSupp;s++)                  /* Objective: Minimize total cost */
  for(c=0; c<NCust; c++)
   XPRBaddterm(ctr, x[s][c], COST[s][c]);
 XPRBsetobj(prob,ctr);                 /* Set objective function */

/****CONSTRAINTS****/
 for(c=0; c<NCust; c++)                /* Satisfy demand of each customer */
 {
  ctr = XPRBnewctr(prob,"Demand", XPRB_G);
  for(s=0;s<NSupp;s++) XPRBaddterm(ctr, x[s][c], 1);
  XPRBaddterm(ctr, NULL, DEMAND[c]);
 }

 for(s=0;s<NSupp;s++)                  /* Keep within supply at each supplier*/
 {
  ctr = XPRBnewctr(prob,"Supply",XPRB_L);
  for(c=0; c<NCust; c++)
   XPRBaddterm(ctr, x[s][c], 1);
  XPRBaddterm(ctr, NULL, SUPPLY[s]);
 }

/****BOUNDS****/
 for(s=0;s<NSupp;s++)
  for(c=0; c<NCust; c++)
   if(IFVAN[s][c]!=0) XPRBsetub(x[s][c], VANCAP);

/****SOLVING + OUTPUT****/
 XPRBexportprob(prob,XPRB_MPS,"delivery");  /* Write out an MPS file */

 XPRBsetsense(prob, XPRB_MINIM);      /* Set objective sense to minimization */
 XPRBlpoptimize(prob, "");            /* Solve the LP-problem */
 printf("Objective: %g\n", XPRBgetobjval(prob));  /* Get objective value */

 for(s=0;s<NSupp;s++)                 /* Print out the solution values */
  for(c=0; c<NCust; c++)
   printf("%s:%g ", XPRBgetvarname(x[s][c]), XPRBgetsol(x[s][c]));
 printf("\n");
}

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

    /**** Array-based constraint formulation ****/
void moddelivery_array(XPRBprob prob)
{
 int s,c;
 XPRBvar x[NSupp][NCust];
 XPRBarrvar va;
 XPRBctr ctr;

/****VARIABLES****/
 for(s=0;s<NSupp;s++)
  for(c=0; c<NCust; c++)
   x[s][c]=XPRBnewvar(prob,XPRB_PL,XPRBnewname("x_s%d",s), 0, XPRB_INFINITY);

/****OBJECTIVE****/
 ctr = XPRBnewctr(prob,"OBJ",XPRB_N);
 for(s=0;s<NSupp;s++)                  /* Objective: Minimize total cost */
  for(c=0; c<NCust; c++)
   XPRBaddterm(ctr, x[s][c], COST[s][c]);
 XPRBsetobj(prob,ctr);                      /* Select objective function */


/****CONSTRAINTS****/
 for(c=0; c<NCust; c++)                /* Satisfy demand of each customer */
 {
  va = XPRBstartarrvar(prob,NSupp,"arr");   /* Define an array of size NSupp */
  for(s=0;s<NSupp;s++)
   XPRBapparrvarel(va, x[s][c]);       /* Add a variable to the array */
  XPRBendarrvar(va);                   /* Terminate definition of the array */
  XPRBnewsum(prob,"Demand", va, XPRB_G, DEMAND[c]);
 }

 for(s=0;s<NSupp;s++)                  /* Keep within supply at each supplier */
 {
  ctr = XPRBnewctr(prob,"Supply",XPRB_L);
  for(c=0; c<NCust; c++)
   XPRBaddterm(ctr, x[s][c], 1);
  XPRBaddterm(ctr, NULL, SUPPLY[s]);
 }

/****BOUNDS****/
 for(s=0;s<NSupp;s++)
  for(c=0; c<NCust; c++)
   if(IFVAN[s][c]!=0) XPRBsetub(x[s][c], VANCAP);

/****SOLVING + OUTPUT****/
 XPRBexportprob(prob,XPRB_MPS,"delivery");  /* Write out an MPS file */

 XPRBsetsense(prob,XPRB_MINIM);             /* Set objective sense to minimization */
 XPRBsolve(prob,"");                        /* Solve the LP-problem */
 printf("Objective: %g\n", XPRBgetobjval(prob));  /* Get objective value */

 for(s=0;s<NSupp;s++)                       /* Print out the solution values */
  for(c=0; c<NCust; c++)
   printf("%s:%g ", XPRBgetvarname(x[s][c]), XPRBgetsol(x[s][c]));
 printf("\n");
}

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

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

/* Initialize data tables to 0: in the van data file some entries that are
 * zero are simply left out, but the function XPRBreadarrline only initializes
 * those elements to 0 that have been read, e.g. a data line ",,," results
 * in the first 4 elements of the array to be set to zero, even if the
 * maximum number of elements to be read (=last parameter of XPRBreadarrline)
 * has a much larger value */
 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 */

#ifdef ARRAY
 moddelivery_array(prob);        /* Constraint formulation using arrays */
#else
 moddelivery(prob);              /* Straight-forward problem formulation */
#endif

 return 0;
}