001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math.ode.nonstiff; 019 020 import static org.junit.Assert.assertTrue; 021 022 import java.io.ByteArrayInputStream; 023 import java.io.ByteArrayOutputStream; 024 import java.io.IOException; 025 import java.io.ObjectInputStream; 026 import java.io.ObjectOutputStream; 027 import java.util.Random; 028 029 import org.apache.commons.math.ode.ContinuousOutputModel; 030 import org.apache.commons.math.ode.DerivativeException; 031 import org.apache.commons.math.ode.IntegratorException; 032 import org.apache.commons.math.ode.TestProblem3; 033 import org.apache.commons.math.ode.sampling.StepHandler; 034 import org.apache.commons.math.ode.sampling.StepInterpolatorTestUtils; 035 import org.junit.Test; 036 037 public class ThreeEighthesStepInterpolatorTest { 038 039 @Test 040 public void derivativesConsistency() 041 throws DerivativeException, IntegratorException { 042 TestProblem3 pb = new TestProblem3(); 043 double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.001; 044 ThreeEighthesIntegrator integ = new ThreeEighthesIntegrator(step); 045 StepInterpolatorTestUtils.checkDerivativesConsistency(integ, pb, 1.0e-10); 046 } 047 048 @Test 049 public void serialization() 050 throws DerivativeException, IntegratorException, 051 IOException, ClassNotFoundException { 052 053 TestProblem3 pb = new TestProblem3(0.9); 054 double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.0003; 055 ThreeEighthesIntegrator integ = new ThreeEighthesIntegrator(step); 056 integ.addStepHandler(new ContinuousOutputModel()); 057 integ.integrate(pb, 058 pb.getInitialTime(), pb.getInitialState(), 059 pb.getFinalTime(), new double[pb.getDimension()]); 060 061 ByteArrayOutputStream bos = new ByteArrayOutputStream(); 062 ObjectOutputStream oos = new ObjectOutputStream(bos); 063 for (StepHandler handler : integ.getStepHandlers()) { 064 oos.writeObject(handler); 065 } 066 067 assertTrue(bos.size () > 700000); 068 assertTrue(bos.size () < 701000); 069 070 ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray()); 071 ObjectInputStream ois = new ObjectInputStream(bis); 072 ContinuousOutputModel cm = (ContinuousOutputModel) ois.readObject(); 073 074 Random random = new Random(347588535632l); 075 double maxError = 0.0; 076 for (int i = 0; i < 1000; ++i) { 077 double r = random.nextDouble(); 078 double time = r * pb.getInitialTime() + (1.0 - r) * pb.getFinalTime(); 079 cm.setInterpolatedTime(time); 080 double[] interpolatedY = cm.getInterpolatedState (); 081 double[] theoreticalY = pb.computeTheoreticalState(time); 082 double dx = interpolatedY[0] - theoreticalY[0]; 083 double dy = interpolatedY[1] - theoreticalY[1]; 084 double error = dx * dx + dy * dy; 085 if (error > maxError) { 086 maxError = error; 087 } 088 } 089 090 assertTrue(maxError > 0.005); 091 092 } 093 094 }