82 lines
2.9 KiB
Java
82 lines
2.9 KiB
Java
// Copyright 2010-2011 Google
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package com.google.ortools.linearsolver.samples;
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import com.google.ortools.linearsolver.MPConstraint;
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import com.google.ortools.linearsolver.MPSolver;
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import com.google.ortools.linearsolver.MPVariable;
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/**
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* Example of linear solver usage.
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*
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*/
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public class LinearSolverExample {
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static {
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System.loadLibrary("jnilinearsolver");
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}
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private static void runFirstLinearExample(int solverType) {
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MPSolver solver = new MPSolver("runFirstLinearExample", solverType);
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double infinity = solver.infinity();
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MPVariable x1 = solver.makeNumVar(0.0, infinity, "x1");
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MPVariable x2 = solver.makeNumVar(0.0, infinity, "x2");
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MPVariable x3 = solver.makeNumVar(0.0, infinity, "x3");
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System.out.println("Number of variables = " + solver.numVariables());
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solver.addObjectiveTerm(x1, 10);
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solver.addObjectiveTerm(x2, 6);
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solver.addObjectiveTerm(x3, 4);
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solver.setMaximization();
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MPConstraint c0 = solver.makeConstraint(-infinity, 100.0);
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c0.addTerm(x1, 1);
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c0.addTerm(x2, 1);
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c0.addTerm(x3, 1);
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MPConstraint c1 = solver.makeConstraint(-infinity, 600.0);
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c1.addTerm(x1, 10);
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c1.addTerm(x2, 4);
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c1.addTerm(x3, 5);
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MPConstraint c2 = solver.makeConstraint(-infinity, 300.0);
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c2.addTerm(x1, 2);
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c2.addTerm(x2, 2);
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c2.addTerm(x3, 6);
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System.out.println("Number of constraints = " + solver.numConstraints());
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// The problem has an optimal solution.
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solver.solve();
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System.out.println("Optimal value = " + solver.objectiveValue());
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System.out.println("x1 = " + x1.solutionValue() +
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" reduced cost = " + x1.reducedCost());
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System.out.println("x2 = " + x2.solutionValue() +
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" reduced cost = " + x2.reducedCost());
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System.out.println("x3 = " + x3.solutionValue() +
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" reduced cost = " + x3.reducedCost());
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System.out.println("c0 dual value = " + c0.dualValue() +
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" activity = " + c0.activity());
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System.out.println("c1 dual value = " + c1.dualValue() +
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" activity = " + c1.activity());
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System.out.println("c2 dual value = " + c2.dualValue() +
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" activity = " + c2.activity());
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}
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public static void main(String[] args) throws Exception {
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runFirstLinearExample(MPSolver.CLP_LINEAR_PROGRAMMING);
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runFirstLinearExample(MPSolver.GLPK_LINEAR_PROGRAMMING);
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}
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}
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