Running a model with multiple data scenarios

/*******************************************************
   Mosel Example Problems
   ====================== 

   file scenar.c
   `````````````
   Executing different scenarios.
   
   (c) 2008 Fair Isaac Corporation
       author: S. Heipcke, 2002
********************************************************/

#include <stdio.h>
#include <string.h>
#include "xprm_mc.h"

int execscenar(const char *FILENAME, double WEIGHT);

#define NSUP 6

double obj, capuse[NSUP], CAP[NSUP];
char SUPNAME[NSUP][64];

int main()
{
 int NSCENAR = 5;
 const char *DEMDATA[] = {"dem1.dat", "dem2.dat", "dem3.dat", "dem4.dat", 
                          "dem5.dat"};
 double WEIGHT[] = {0.4, 0.15, 0.1, 0.25, 0.1};
 int i,s;
 double fact = 0;

 if(XPRMinit())                         /* Initialize Mosel */
  return 1;
                                        /* Execute all scenarios */
 for(i=0;i<NSCENAR;i++) if(execscenar(DEMDATA[i], WEIGHT[i])) fact+=WEIGHT[i];
 fact= 1/fact;
                                        /* Print out aggregate results */
 printf("Weighted average objective: %g\n", obj*fact);
 for(s=0;s<NSUP;s++) 
  printf("%s: %g (%g%% of %g)\n", SUPNAME[s], capuse[s]*fact, 
         capuse[s]*fact/CAP[s]*100, CAP[s]);

 return 0;
}

/**** Run a scenario and retrieve its results ****/
int execscenar(const char *FILENAME, double WEIGHT)
{
 XPRMmodel mod;
 XPRMalltypes rvalue;
 XPRMarray darr, varr;
 XPRMset set[1];
 XPRMmpvar x;
 int indices[2], result;
 char params[128];

 sprintf(params, "DEMFILE=Data/%s", FILENAME);

                                          /* Execute model file 'scenar.mos' */
 if(XPRMexecmod(NULL,"scenar.mos",params,&result,&mod))
 { printf("Problem %s not executed.\n", FILENAME); return 0; }
 
                                          /* Test whether a solution is found */
 if((XPRMgetprobstat(mod)&XPRM_PBRES)!=XPRM_PBOPT)
 { printf("Demand scenario %s is infeasible.\n", FILENAME); return 0; }

/* Get the objective function value */
 obj += WEIGHT*XPRMgetobjval(mod);                         

/* At first execution: get 'CAP' data and the 'Suppliers' index set for
   pretty solution printout */
 if(!strcmp(FILENAME, "dem1.dat"))
 {
  XPRMfindident(mod, "CAP", &rvalue);     /* Get the model object 'CAP' */
  darr = rvalue.array;
  XPRMgetarrsets(darr, set);              /* Get the index set of 'CAP' */
  XPRMgetfirstarrentry(darr, indices);    /* Get the first index tuple */
  do
  {
   strcpy(SUPNAME[indices[0]-1], 
     XPRMgetelsetval(set[0], indices[0], &rvalue)->string);
   XPRMgetarrval(darr, indices, &(CAP[indices[0]-1]));
  } while(!XPRMgetnextarrentry(darr, indices));  /* Get the next index tuple */
 }

/* At every execution: get the solution for variables 'x' */
 XPRMfindident(mod, "x", &rvalue);        /* Get the model object 'x' */
 varr = rvalue.array;
 XPRMgetfirstarrtruentry(varr, indices); /* Get the first entry of array varr
                                             (we know that the array is sparse 
                                             and has two dimensions) */
 do
 {
  XPRMgetarrval(varr, indices, &x);       /* Get the corresponding variable */
  capuse[indices[0]-1] += WEIGHT*XPRMgetvsol(mod,x);   /* Save the sol. value */
/*  printf("<%d,%d:%g>\n", indices[0], indices[1], XPRMgetvsol(mod,x)); */
 } while(!XPRMgetnextarrtruentry(varr, indices));  
                                          /* Get the next index tuple */
 return 1;
}

(!*******************************************************
  Mosel Example Problems
  ======================

  file scenar.mos
  ```````````````
  Transportation example (multiple scenarios).

  (c) 2008 Fair Isaac Corporation
      author: S.Heipcke, 2002, rev. June 2018
*********************************************************!)

model "Scenario"
 uses "mmxprs"

 parameters
  DEMFILE="Data/dem1.dat"
 end-parameters
 
 public declarations
  Suppliers: set of string                  ! Set of suppliers
  Customers: set of string                  ! Set of customers
  COST: dynamic array(Suppliers,Customers) of real  ! Cost per supplier-customer pair
  CAP: array(Suppliers) of real             ! Production capacity
  DEM: array(Customers) of real             ! Demand by customers

  x: dynamic array(Suppliers,Customers) of mpvar    ! Transported quantities
 end-declarations
 
 initializations from "Data/supply.dat"
  COST CAP
 end-initializations
 
 initializations from DEMFILE
  DEM as "DEMAND"
 end-initializations  

 forall(s in Suppliers, c in Customers | exists(COST(s,c))) create(x(s,c))

! Objective: minimize total cost
 MinCost:= 
  sum(s in Suppliers, c in Customers | exists(COST(s,c))) COST(s,c) * x(s,c)

! Limits on production capacities
 forall(s in Suppliers) sum(c in Customers) x(s,c) <= CAP(s)

! Satisfy customer demands
 forall(c in Customers) sum(s in Suppliers) x(s,c) >= DEM(c) 

 minimize(MinCost)

 writeln("Demand scenario: ", DEMFILE)
 
(! 
 forall(s in Suppliers, c in Customers)
  if(getsol(x(s,c))>0) then
   writeln(s," (", CAP(s), ") -> ", c, " (", DEM(c), "): ", 
       getsol(x(s,c)) )
  end-if
!)

 if(getprobstat=XPRS_OPT) then
  writeln("Total cost: ", getobjval)
  forall(s in Suppliers) writeln(s, ": ", getsol(sum(c in Customers) x(s,c)) )
 end-if
 
end-model