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 org.apache.commons.math.ode.DerivativeException;
21
22 /**
23 * This interface represents a handler that should be called after
24 * each successful fixed step.
25
26 * <p>This interface should be implemented by anyone who is interested
27 * in getting the solution of an ordinary differential equation at
28 * fixed time steps. Objects implementing this interface should be
29 * wrapped within an instance of {@link StepNormalizer} that itself
30 * is used as the general {@link StepHandler} by the integrator. The
31 * {@link StepNormalizer} object is called according to the integrator
32 * internal algorithms and it calls objects implementing this
33 * interface as necessary at fixed time steps.</p>
34 *
35 * @see StepHandler
36 * @see StepNormalizer
37 * @version $Revision: 785473 $ $Date: 2009-06-17 00:02:35 -0400 (Wed, 17 Jun 2009) $
38 * @since 1.2
39 */
40
41 public interface FixedStepHandler {
42
43 /**
44 * Handle the last accepted step
45 * @param t time of the current step
46 * @param y state vector at t. For efficiency purposes, the {@link
47 * StepNormalizer} class reuses the same array on each call, so if
48 * the instance wants to keep it across all calls (for example to
49 * provide at the end of the integration a complete array of all
50 * steps), it should build a local copy store this copy.
51 * @param yDot derivatives of the state vector state vector at t.
52 * For efficiency purposes, the {@link StepNormalizer} class reuses
53 * the same array on each call, so if
54 * the instance wants to keep it across all calls (for example to
55 * provide at the end of the integration a complete array of all
56 * steps), it should build a local copy store this copy.
57 * @param isLast true if the step is the last one
58 * @throws DerivativeException if some error condition is encountered
59 */
60 public void handleStep(double t, double[] y, double[] yDot, boolean isLast)
61 throws DerivativeException;
62
63 }