package examples;

/* --------------------------------------------------------------------------

* File: FixCost1.java

* Version 12.9.0

* --------------------------------------------------------------------------

* Licensed Materials - Property of IBM

* 5725-A06 5725-A29 5724-Y48 5724-Y49 5724-Y54 5724-Y55 5655-Y21

* Copyright IBM Corporation 2001, 2019. All Rights Reserved.

*

* US Government Users Restricted Rights - Use, duplication or

* disclosure restricted by GSA ADP Schedule Contract with

* IBM Corp.

* --------------------------------------------------------------------------

*

* Problem Description

* -------------------

*

* A company must produce a product on a set of machines.

* Each machine has limited capacity.

* Producing a product on a machine has both a fixed cost

* and a cost per unit of production.

*

* Minimize the sum of fixed and variable costs so that the

* company exactly meets demand.

*/

import ilog.concert.*;

import ilog.cplex.*;

public class FixCost1 {

static int _nbMachines = 6;

static double[] _cost = { 15.0, 20.0, 45.0, 64.0, 12.0, 56.0 };

static double[] _capacity = { 100.0, 20.0, 405.0, 264.0, 12.0, 256.0 };

static double[] _fixedCost = { 1900.0, 820.0, 805.0, 464.0, 3912.0, 556.0 };

static double _demand = 22.0;

public static void main(String[] args) {

try {

IloCplex cplex = new IloCplex();

IloNumVar[] fused = cplex.boolVarArray(_nbMachines);

IloNumVar[] x = cplex.numVarArray(_nbMachines, 0.0, Double.MAX_VALUE);

// Objective: minimize the sum of fixed and variable costs

cplex.addMinimize(cplex.sum(cplex.scalProd(_cost, x), cplex.scalProd(fused, _fixedCost)));

for (int i = 0; i < _nbMachines; i++) {

// Constraint: respect capacity constraint on machine 'i'

cplex.addLe(x[i], _capacity[i]);

// Constraint: only produce product on machine 'i' if it is 'used'

// (to capture fixed cost of using machine 'i')

cplex.addLe(x[i], cplex.prod(10000, fused[i]));

}

// Constraint: meet demand

cplex.addEq(cplex.sum(x), _demand);

if (cplex.solve()) {

System.out.println("Solution status: " + cplex.getStatus());

System.out.println("Obj " + cplex.getObjValue());

// 完整性容错，指定整数变量可与某个整数相差且视为可行的偏差

double eps = cplex.getParam(IloCplex.Param.MIP.Tolerances.Integrality);

for (int i = 0; i < _nbMachines; i++)

if (cplex.getValue(fused[i]) > eps)

System.out.println("E" + i + " is used for " + cplex.getValue(x[i]));

System.out.println();

System.out.println("----------------------------------------");

}

cplex.end();

} catch (IloException exc) {

System.err.println("Concert exception '" + exc + "' caught");

}

}

}

/*

* Solution Obj 1788 E5 is used for 22

*/