| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.commons.math4.legacy.ode.nonstiff; |
| |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.util.Random; |
| |
| import org.apache.commons.math4.legacy.exception.DimensionMismatchException; |
| import org.apache.commons.math4.legacy.exception.MaxCountExceededException; |
| import org.apache.commons.math4.legacy.exception.NoBracketingException; |
| import org.apache.commons.math4.legacy.exception.NumberIsTooSmallException; |
| import org.apache.commons.math4.legacy.ode.ContinuousOutputModel; |
| import org.apache.commons.math4.legacy.ode.TestProblem3; |
| import org.apache.commons.math4.legacy.ode.sampling.StepHandler; |
| import org.apache.commons.math4.legacy.ode.sampling.StepInterpolatorTestUtils; |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| public class ClassicalRungeKuttaStepInterpolatorTest { |
| |
| @Test |
| public void derivativesConsistency() |
| throws DimensionMismatchException, NumberIsTooSmallException, |
| MaxCountExceededException, NoBracketingException { |
| TestProblem3 pb = new TestProblem3(); |
| double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.001; |
| ClassicalRungeKuttaIntegrator integ = new ClassicalRungeKuttaIntegrator(step); |
| StepInterpolatorTestUtils.checkDerivativesConsistency(integ, pb, 0.01, 6.6e-12); |
| } |
| |
| @Test |
| public void serialization() |
| throws IOException, ClassNotFoundException, |
| DimensionMismatchException, NumberIsTooSmallException, |
| MaxCountExceededException, NoBracketingException { |
| |
| TestProblem3 pb = new TestProblem3(0.9); |
| double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.0003; |
| ClassicalRungeKuttaIntegrator integ = new ClassicalRungeKuttaIntegrator(step); |
| integ.addStepHandler(new ContinuousOutputModel()); |
| integ.integrate(pb, |
| pb.getInitialTime(), pb.getInitialState(), |
| pb.getFinalTime(), new double[pb.getDimension()]); |
| |
| ByteArrayOutputStream bos = new ByteArrayOutputStream(); |
| ObjectOutputStream oos = new ObjectOutputStream(bos); |
| for (StepHandler handler : integ.getStepHandlers()) { |
| oos.writeObject(handler); |
| } |
| |
| Assert.assertTrue(bos.size () > 880000); |
| Assert.assertTrue(bos.size () < 900000); |
| |
| ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray()); |
| ObjectInputStream ois = new ObjectInputStream(bis); |
| ContinuousOutputModel cm = (ContinuousOutputModel) ois.readObject(); |
| |
| Random random = new Random(347588535632L); |
| double maxError = 0.0; |
| for (int i = 0; i < 1000; ++i) { |
| double r = random.nextDouble(); |
| double time = r * pb.getInitialTime() + (1.0 - r) * pb.getFinalTime(); |
| cm.setInterpolatedTime(time); |
| double[] interpolatedY = cm.getInterpolatedState (); |
| double[] theoreticalY = pb.computeTheoreticalState(time); |
| double dx = interpolatedY[0] - theoreticalY[0]; |
| double dy = interpolatedY[1] - theoreticalY[1]; |
| double error = dx * dx + dy * dy; |
| if (error > maxError) { |
| maxError = error; |
| } |
| } |
| |
| Assert.assertTrue(maxError > 0.005); |
| |
| } |
| |
| } |