1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.math.ode.sampling;
19  
20  import static org.junit.Assert.assertTrue;
21  
22  import java.io.ByteArrayInputStream;
23  import java.io.ByteArrayOutputStream;
24  import java.io.IOException;
25  import java.io.ObjectInputStream;
26  import java.io.ObjectOutputStream;
27  import java.util.Random;
28  
29  import org.apache.commons.math.ode.ContinuousOutputModel;
30  import org.apache.commons.math.ode.DerivativeException;
31  import org.apache.commons.math.ode.IntegratorException;
32  import org.apache.commons.math.ode.TestProblem1;
33  import org.apache.commons.math.ode.TestProblem3;
34  import org.apache.commons.math.ode.nonstiff.AdamsBashforthIntegrator;
35  import org.junit.Test;
36  
37  public class NordsieckStepInterpolatorTest {
38  
39      @Test
40      public void derivativesConsistency()
41      throws DerivativeException, IntegratorException {
42          TestProblem3 pb = new TestProblem3();
43          AdamsBashforthIntegrator integ = new AdamsBashforthIntegrator(4, 0.0, 1.0, 1.0e-10, 1.0e-10);
44          StepInterpolatorTestUtils.checkDerivativesConsistency(integ, pb, 7e-10);
45      }
46  
47      @Test
48      public void serialization()
49      throws DerivativeException, IntegratorException,
50      IOException, ClassNotFoundException {
51  
52          TestProblem1 pb = new TestProblem1();
53          AdamsBashforthIntegrator integ = new AdamsBashforthIntegrator(4, 0.0, 1.0, 1.0e-10, 1.0e-10);
54          integ.addStepHandler(new ContinuousOutputModel());
55          integ.integrate(pb,
56                          pb.getInitialTime(), pb.getInitialState(),
57                          pb.getFinalTime(), new double[pb.getDimension()]);
58  
59          ByteArrayOutputStream bos = new ByteArrayOutputStream();
60          ObjectOutputStream    oos = new ObjectOutputStream(bos);
61          for (StepHandler handler : integ.getStepHandlers()) {
62              oos.writeObject(handler);
63          }
64  
65          assertTrue(bos.size () >  20000);
66          assertTrue(bos.size () <  25000);
67  
68          ByteArrayInputStream  bis = new ByteArrayInputStream(bos.toByteArray());
69          ObjectInputStream     ois = new ObjectInputStream(bis);
70          ContinuousOutputModel cm  = (ContinuousOutputModel) ois.readObject();
71  
72          Random random = new Random(347588535632l);
73          double maxError = 0.0;
74          for (int i = 0; i < 1000; ++i) {
75              double r = random.nextDouble();
76              double time = r * pb.getInitialTime() + (1.0 - r) * pb.getFinalTime();
77              cm.setInterpolatedTime(time);
78              double[] interpolatedY = cm.getInterpolatedState ();
79              double[] theoreticalY  = pb.computeTheoreticalState(time);
80              double dx = interpolatedY[0] - theoreticalY[0];
81              double dy = interpolatedY[1] - theoreticalY[1];
82              double error = dx * dx + dy * dy;
83              if (error > maxError) {
84                  maxError = error;
85              }
86          }
87  
88          assertTrue(maxError < 1.0e-6);
89  
90      }
91  
92  }