// --------------------------------------------------------------------------
// File: examples/src/Diet.java
// Version 8.1
// --------------------------------------------------------------------------
// Copyright (C) 2001-2002 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
// nutrPerFood[i][j] nutrition amount of nutrient i in food j
//
// Modeling 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]
//
import ilog.concert.*;
import ilog.cplex.*;
public class Diet {
static class Data {
int nFoods;
int nNutrs;
double[] foodCost;
double[] foodMin;
double[] foodMax;
double[] nutrMin;
double[] nutrMax;
double[][] nutrPerFood;
Data(String filename) throws IloException, java.io.IOException,
InputDataReader.InputDataReaderException {
InputDataReader reader = new InputDataReader(filename);
foodCost = reader.readDoubleArray();
foodMin = reader.readDoubleArray();
foodMax = reader.readDoubleArray();
nutrMin = reader.readDoubleArray();
nutrMax = reader.readDoubleArray();
nutrPerFood = reader.readDoubleArrayArray();
nFoods = foodMax.length;
nNutrs = nutrMax.length;
if ( nFoods != foodMin.length ||
nFoods != foodMax.length )
throw new IloException("inconsistent data in file " + filename);
if ( nNutrs != nutrMin.length ||
nNutrs != nutrPerFood.length )
throw new IloException("inconsistent data in file " + filename);
for (int i = 0; i < nNutrs; ++i) {
if ( nutrPerFood[i].length != nFoods )
throw new IloException("inconsistent data in file " + filename);
}
}
}
static void buildModelByRow(IloModeler model,
Data data,
IloNumVar[] Buy,
IloNumVarType type) throws IloException {
int nFoods = data.nFoods;
int nNutrs = data.nNutrs;
for (int j = 0; j < nFoods; j++) {
Buy[j] = model.numVar(data.foodMin[j], data.foodMax[j], type);
}
model.addMinimize(model.scalProd(data.foodCost, Buy));
for (int i = 0; i < nNutrs; i++) {
model.addRange(data.nutrMin[i],
model.scalProd(data.nutrPerFood[i], Buy),
data.nutrMax[i]);
}
}
static void buildModelByColumn(IloMPModeler model,
Data data,
IloNumVar[] Buy,
IloNumVarType type) throws IloException {
int nFoods = data.nFoods;
int nNutrs = data.nNutrs;
IloObjective cost = model.addMinimize();
IloRange[] constraint = new IloRange[nNutrs];
for (int i = 0; i < nNutrs; i++) {
constraint[i] = model.addRange(data.nutrMin[i], data.nutrMax[i]);
}
for (int j = 0; j < nFoods; j++) {
IloColumn col = model.column(cost, data.foodCost[j]);
for (int i = 0; i < nNutrs; i++) {
col = col.and(model.column(constraint[i], data.nutrPerFood[i][j]));
}
Buy[j] = model.numVar(col, data.foodMin[j], data.foodMax[j], type);
}
}
public static void main(String[] args) {
try {
String filename = "../../../examples/data/diet.dat";
boolean byColumn = false;
IloNumVarType varType = IloNumVarType.Float;
for (int i = 0; i < args.length; i++) {
if ( args[i].charAt(0) == '-') {
switch (args[i].charAt(1)) {
case 'c':
byColumn = true;
break;
case 'i':
varType = IloNumVarType.Int;
break;
default:
usage();
return;
}
}
else {
filename = args[i];
break;
}
}
Data data = new Data(filename);
int nFoods = data.nFoods;
int nNutrs = data.nNutrs;
// Build model
IloCplex cplex = new IloCplex();
IloNumVar[] Buy = new IloNumVar[nFoods];
if ( byColumn ) buildModelByColumn(cplex, data, Buy, varType);
else buildModelByRow (cplex, data, Buy, varType);
// Solve model
if ( cplex.solve() ) {
System.out.println();
System.out.println("Solution status = " + cplex.getStatus());
System.out.println();
System.out.println(" cost = " + cplex.getObjValue());
for (int i = 0; i < nFoods; i++) {
System.out.println(" Buy" + i + " = " + cplex.getValue(Buy[i]));
}
System.out.println();
}
cplex.end();
}
catch (IloException ex) {
System.out.println("Concert Error: " + ex);
}
catch (InputDataReader.InputDataReaderException ex) {
System.out.println("Data Error: " + ex);
}
catch (java.io.IOException ex) {
System.out.println("IO Error: " + ex);
}
}
static void usage() {
System.out.println(" ");
System.out.println("usage: java Diet [options] <data file>");
System.out.println("options: -c build model by column");
System.out.println(" -i use integer variables");
System.out.println(" ");
}
}
/* Sample output
Solution status = Optimal
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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