| career | drupal | java | mac | mysql | perl | scala | uml | unix  

Commons Math example source code file (

This example Commons Math source code file ( is included in the "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Math tags/keywords

bytearrayoutputstream, continuousoutputmodel, continuousoutputmodel, derivativeexception, gillintegrator, gillintegrator, integratorexception, io, objectinputstream, objectoutputstream, random, test, test, testproblem3, testproblem3, util

The Commons Math 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
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * 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.assertTrue;

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.nonstiff.GillIntegrator;
import org.apache.commons.math.ode.sampling.StepHandler;
import org.apache.commons.math.ode.sampling.StepInterpolatorTestUtils;
import org.junit.Test;

public class GillStepInterpolatorTest {

  public void testDerivativesConsistency()
  throws DerivativeException, IntegratorException {
    TestProblem3 pb = new TestProblem3();
    double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.001;
    GillIntegrator integ = new GillIntegrator(step);
    StepInterpolatorTestUtils.checkDerivativesConsistency(integ, pb, 1.0e-10);

  public void serialization()
    throws DerivativeException, IntegratorException,
           IOException, ClassNotFoundException {

    TestProblem3 pb = new TestProblem3(0.9);
    double step = (pb.getFinalTime() - pb.getInitialTime()) * 0.0003;
    GillIntegrator integ = new GillIntegrator(step);
    integ.addStepHandler(new ContinuousOutputModel());
                    pb.getInitialTime(), pb.getInitialState(),
                    pb.getFinalTime(), new double[pb.getDimension()]);

    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream    oos = new ObjectOutputStream(bos);
    for (StepHandler handler : integ.getStepHandlers()) {

    assertTrue(bos.size () > 700000);
    assertTrue(bos.size () < 701000);

    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();
      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 < 0.003);



Other Commons Math examples (source code examples)

Here is a short list of links related to this Commons Math source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller


new blog posts


Copyright 1998-2021 Alvin Alexander,
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.