Commons Math example source code file (DummyStepInterpolatorTest.java)

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

Java - Commons Math tags/keywords

badstepinterpolator, badstepinterpolator, bytearrayinputstream, bytearrayoutputstream, derivativeexception, derivativeexception, dummystepinterpolator, dummystepinterpolator, dummystepinterpolatortest, io, ioexception, objectinputstream, objectoutputstream, test, test

The Commons Math DummyStepInterpolatorTest.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.sampling;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.io.ByteArrayOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;

import org.apache.commons.math.ode.DerivativeException;
import org.apache.commons.math.ode.sampling.AbstractStepInterpolator;
import org.apache.commons.math.ode.sampling.DummyStepInterpolator;
import org.junit.Test;

public class DummyStepInterpolatorTest {

  @Test
  public void testNoReset() throws DerivativeException {

    double[]   y    =   { 0.0, 1.0, -2.0 };
    DummyStepInterpolator interpolator = new DummyStepInterpolator(y, new double[y.length], true);
    interpolator.storeTime(0);
    interpolator.shift();
    interpolator.storeTime(1);

    double[] result = interpolator.getInterpolatedState();
    for (int i = 0; i < result.length; ++i) {
      assertTrue(Math.abs(result[i] - y[i]) < 1.0e-10);
    }

  }

  @Test
  public void testFixedState()
    throws DerivativeException {

    double[]   y    =   { 1.0, 3.0, -4.0 };
    DummyStepInterpolator interpolator = new DummyStepInterpolator(y, new double[y.length], true);
    interpolator.storeTime(0);
    interpolator.shift();
    interpolator.storeTime(1);

    interpolator.setInterpolatedTime(0.1);
    double[] result = interpolator.getInterpolatedState();
    for (int i = 0; i < result.length; ++i) {
        assertTrue(Math.abs(result[i] - y[i]) < 1.0e-10);
    }

    interpolator.setInterpolatedTime(0.5);
    result = interpolator.getInterpolatedState();
    for (int i = 0; i < result.length; ++i) {
        assertTrue(Math.abs(result[i] - y[i]) < 1.0e-10);
    }

  }

  @Test
  public void testSerialization()
  throws DerivativeException, IOException, ClassNotFoundException {

    double[]   y    =   { 0.0, 1.0, -2.0 };
    DummyStepInterpolator interpolator = new DummyStepInterpolator(y, new double[y.length], true);
    interpolator.storeTime(0);
    interpolator.shift();
    interpolator.storeTime(1);

    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream    oos = new ObjectOutputStream(bos);
    oos.writeObject(interpolator);

    assertTrue(bos.size () > 150);
    assertTrue(bos.size () < 250);

    ByteArrayInputStream  bis = new ByteArrayInputStream(bos.toByteArray());
    ObjectInputStream     ois = new ObjectInputStream(bis);
    DummyStepInterpolator dsi = (DummyStepInterpolator) ois.readObject();

    dsi.setInterpolatedTime(0.5);
    double[] result = dsi.getInterpolatedState();
    for (int i = 0; i < result.length; ++i) {
        assertTrue(Math.abs(result[i] - y[i]) < 1.0e-10);
    }

  }

  @Test
  public void testImpossibleSerialization()
  throws IOException {

    double[] y = { 0.0, 1.0, -2.0 };
    AbstractStepInterpolator interpolator = new BadStepInterpolator(y, true);
    interpolator.storeTime(0);
    interpolator.shift();
    interpolator.storeTime(1);

    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    ObjectOutputStream    oos = new ObjectOutputStream(bos);
    try {
        oos.writeObject(interpolator);
        fail("an exception should have been thrown");
    } catch (IOException ioe) {
        // expected behavior
        assertEquals(0, ioe.getMessage().length());
    } catch (Exception e) {
        fail("wrong exception caught");
    }

  }

  private static class BadStepInterpolator extends DummyStepInterpolator {
      @SuppressWarnings("unused")
      public BadStepInterpolator() {
      }
      public BadStepInterpolator(double[] y, boolean forward) {
          super(y, new double[y.length], forward);
      }
      @Override
      protected void doFinalize()
      throws DerivativeException {
          throw new DerivativeException(null);
      }
  }

}