1 /*
2 * Licensed to the Hipparchus project 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 Hipparchus project 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 * https://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.hipparchus.ode.sampling;
19
20 import org.hipparchus.ode.ODEStateAndDerivative;
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 ODEStepHandler} 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 ODEStepHandler
36 * @see StepNormalizer
37 */
38
39 public interface ODEFixedStepHandler {
40
41 /** Initialize step handler at the start of an ODE integration.
42 * <p>
43 * This method is called once at the start of the integration. It
44 * may be used by the step handler to initialize some internal data
45 * if needed.
46 * </p>
47 * <p>
48 * The default implementation does nothing.
49 * </p>
50 * @param initialState initial time, state vector and derivative
51 * @param finalTime target time for the integration
52 */
53 default void init(ODEStateAndDerivative initialState, double finalTime) {
54 // nothing by default
55 }
56
57 /**
58 * Handle the last accepted step
59 * @param state current state
60 * @param isLast true if the step is the last one
61 */
62 void handleStep(ODEStateAndDerivative state, boolean isLast);
63
64 }