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Commons Math example source code file (GraggBulirschStoerStepInterpolatorTest.java)
The Commons Math GraggBulirschStoerStepInterpolatorTest.java source code/* * 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.math.ode.nonstiff; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertTrue; 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.math.ode.ContinuousOutputModel; import org.apache.commons.math.ode.DerivativeException; import org.apache.commons.math.ode.IntegratorException; import org.apache.commons.math.ode.TestProblem3; import org.apache.commons.math.ode.sampling.StepHandler; import org.apache.commons.math.ode.sampling.StepInterpolator; import org.apache.commons.math.ode.sampling.StepInterpolatorTestUtils; import org.junit.Test; public class GraggBulirschStoerStepInterpolatorTest { @Test public void derivativesConsistency() throws DerivativeException, IntegratorException { TestProblem3 pb = new TestProblem3(0.9); double minStep = 0; double maxStep = pb.getFinalTime() - pb.getInitialTime(); double absTolerance = 1.0e-8; double relTolerance = 1.0e-8; GraggBulirschStoerIntegrator integ = new GraggBulirschStoerIntegrator(minStep, maxStep, absTolerance, relTolerance); StepInterpolatorTestUtils.checkDerivativesConsistency(integ, pb, 1.0e-8); } @Test public void serialization() throws DerivativeException, IntegratorException, IOException, ClassNotFoundException { TestProblem3 pb = new TestProblem3(0.9); double minStep = 0; double maxStep = pb.getFinalTime() - pb.getInitialTime(); double absTolerance = 1.0e-8; double relTolerance = 1.0e-8; GraggBulirschStoerIntegrator integ = new GraggBulirschStoerIntegrator(minStep, maxStep, absTolerance, relTolerance); 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); } assertTrue(bos.size () > 33000); assertTrue(bos.size () < 34000); 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; } } assertTrue(maxError < 5.0e-10); } @Test public void checklone() throws DerivativeException, IntegratorException { TestProblem3 pb = new TestProblem3(0.9); double minStep = 0; double maxStep = pb.getFinalTime() - pb.getInitialTime(); double scalAbsoluteTolerance = 1.0e-8; double scalRelativeTolerance = scalAbsoluteTolerance; GraggBulirschStoerIntegrator integ = new GraggBulirschStoerIntegrator(minStep, maxStep, scalAbsoluteTolerance, scalRelativeTolerance); integ.addStepHandler(new StepHandler() { public void handleStep(StepInterpolator interpolator, boolean isLast) throws DerivativeException { StepInterpolator cloned = interpolator.copy(); double tA = cloned.getPreviousTime(); double tB = cloned.getCurrentTime(); double halfStep = Math.abs(tB - tA) / 2; assertEquals(interpolator.getPreviousTime(), tA, 1.0e-12); assertEquals(interpolator.getCurrentTime(), tB, 1.0e-12); for (int i = 0; i < 10; ++i) { double t = (i * tB + (9 - i) * tA) / 9; interpolator.setInterpolatedTime(t); assertTrue(Math.abs(cloned.getInterpolatedTime() - t) > (halfStep / 10)); cloned.setInterpolatedTime(t); assertEquals(t, cloned.getInterpolatedTime(), 1.0e-12); double[] referenceState = interpolator.getInterpolatedState(); double[] cloneState = cloned.getInterpolatedState(); for (int j = 0; j < referenceState.length; ++j) { assertEquals(referenceState[j], cloneState[j], 1.0e-12); } } } public boolean requiresDenseOutput() { return true; } public void reset() { } }); integ.integrate(pb, pb.getInitialTime(), pb.getInitialState(), pb.getFinalTime(), new double[pb.getDimension()]); } } Other Commons Math examples (source code examples)Here is a short list of links related to this Commons Math GraggBulirschStoerStepInterpolatorTest.java source code file: |
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