// -------------------------------------------------------------- -*- C++ -*-
// File: examples/src/ilodiet.cpp
// Version 8.1
// --------------------------------------------------------------------------
// Copyright (C) 1999-2002 by ILOG.
// All Rights Reserved.
// Permission is expressly granted to use this example in the
// course of developing applications that use ILOG products.
// --------------------------------------------------------------------------
//
// A dietary model.
//
// Input data:
// foodMin[j] minimum amount of food j to use
// foodMax[j] maximum amount of food j to use
// foodCost[j] cost for one unit of food j
// nutrMin[i] minimum amount of nutrient i
// nutrMax[i] maximum amount of nutrient i
// nutrPer[i][j] nutrition amount of nutrient i in food j
//
// Modelling variables:
// Buy[j] amount of food j to purchase
//
// Objective:
// minimize sum(j) Buy[j] * foodCost[j]
//
// Constraints:
// forall foods i: nutrMin[i] <= sum(j) Buy[j] * nutrPer[i][j] <= nutrMax[j]
//
#include <ilcplex/ilocplex.h>
ILOSTLBEGIN
void usage(const char* name) {
cerr << endl;
cerr << "usage: " << name << " [options] <file>" << endl;
cerr << "options: -c build model by column" << endl;
cerr << " -i use integer variables" << endl;
cerr << endl;
}
typedef IloArray<IloNumArray> IloNumArray2;
void
buildModelByRow(IloModel mod,
IloNumVarArray Buy,
const IloNumArray foodMin,
const IloNumArray foodMax,
const IloNumArray foodCost,
const IloNumArray nutrMin,
const IloNumArray nutrMax,
const IloNumArray2 nutrPer,
IloNumVar::Type type) {
IloEnv env = mod.getEnv();
Buy.clear();
IloNumVarArray tmp(env, foodMin, foodMax, type);
Buy.add(tmp);
tmp.end();
IloInt i, j;
IloInt n = foodCost.getSize();
IloInt m = nutrMin.getSize();
mod.add(IloMinimize(env, IloScalProd(Buy,foodCost)));
for (i = 0; i < m; i++) {
IloExpr expr(env);
for (j = 0; j < n; j++) {
expr += Buy[j] * nutrPer[i][j];
}
mod.add(nutrMin[i] <= expr <= nutrMax[i]);
expr.end();
}
}
void
buildModelByColumn(IloModel mod,
IloNumVarArray Buy,
const IloNumArray foodMin,
const IloNumArray foodMax,
const IloNumArray foodCost,
const IloNumArray nutrMin,
const IloNumArray nutrMax,
const IloNumArray2 nutrPer,
IloNumVar::Type type) {
IloEnv env = mod.getEnv();
IloInt i, j;
IloInt n = foodCost.getSize();
IloInt m = nutrMin.getSize();
IloRangeArray range (env, nutrMin, nutrMax);
mod.add(range);
IloObjective cost = IloAdd(mod, IloMinimize(env));
for (j = 0; j < n; j++) {
IloNumColumn col = cost(foodCost[j]);
for (i = 0; i < m; i++) {
col += range[i](nutrPer[i][j]);
}
Buy.add(IloNumVar(col, foodMin[j], foodMax[j], type));
col.end();
}
range.end();
}
int
main(int argc, char **argv)
{
IloEnv env;
try {
const char* filename = "../../../examples/data/diet.dat";
IloBool byColumn = IloFalse;
IloNumVar::Type varType = ILOFLOAT;
IloInt i;
for (i = 1; i < argc; ++i) {
if (argv[i][0] == '-') {
switch (argv[i][1]) {
case 'c':
byColumn = IloTrue;
break;
case 'i':
varType = ILOINT;
break;
default:
usage(argv[0]);
throw (-1);
}
}
else {
filename = argv[i];
break;
}
}
ifstream file(filename);
if ( !file ) {
cerr << "ERROR: could not open file '" << filename
<< "' for reading" << endl;
usage(argv[0]);
throw (-1);
}
// model data
IloNumArray foodCost(env), foodMin(env), foodMax(env);
IloNumArray nutrMin(env), nutrMax(env);
IloNumArray2 nutrPer(env);
file >> foodCost >> foodMin >> foodMax;
file >> nutrMin >> nutrMax;
file >> nutrPer;
IloInt nFoods = foodCost.getSize();
IloInt nNutr = nutrMin.getSize();
if ( foodMin.getSize() != nFoods ||
foodMax.getSize() != nFoods ||
nutrPer.getSize() != nNutr ||
nutrMax.getSize() != nNutr ) {
cerr << "ERROR: Data file '" << filename
<< "' contains inconsistent data" << endl;
throw (-1);
}
for (i = 0; i < nNutr; ++i) {
if (nutrPer[i].getSize() != nFoods) {
cerr << "ERROR: Data file '" << argv[0]
<< "' contains inconsistent data" << endl;
throw (-1);
}
}
// Build model
IloModel mod(env);
IloNumVarArray Buy(env);
if ( byColumn ) {
buildModelByColumn(mod, Buy, foodMin, foodMax, foodCost,
nutrMin, nutrMax, nutrPer, varType);
}
else {
buildModelByRow(mod, Buy, foodMin, foodMax, foodCost,
nutrMin, nutrMax, nutrPer, varType);
}
// Solve model
IloCplex cplex(mod);
cplex.exportModel("diet.sav");
cplex.solve();
cplex.out() << "solution status = " << cplex.getStatus() << endl;
cplex.out() << endl;
cplex.out() << "cost = " << cplex.getObjValue() << endl;
for (i = 0; i < foodCost.getSize(); i++) {
cplex.out() << " Buy" << i << " = " << cplex.getValue(Buy[i]) << endl;
}
}
catch (IloException& ex) {
cerr << "Error: " << ex << endl;
}
catch (...) {
cerr << "Error" << endl;
}
env.end();
return 0;
}
/*
cost = 14.8557
Buy0 = 4.38525
Buy1 = 0
Buy2 = 0
Buy3 = 0
Buy4 = 0
Buy5 = 6.14754
Buy6 = 0
Buy7 = 3.42213
Buy8 = 0
*/
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