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 /**
24 * This interface represents a handler that should be called after
25 * each successful step.
26 *
27 * <p>The ODE integrators compute the evolution of the state vector at
28 * some grid points that depend on their own internal algorithm. Once
29 * they have found a new grid point (possibly after having computed
30 * several evaluation of the derivative at intermediate points), they
31 * provide it to objects implementing this interface. These objects
32 * typically either ignore the intermediate steps and wait for the
33 * last one, store the points in an ephemeris, or forward them to
34 * specialized processing or output methods.</p>
35 *
36 * @see org.hipparchus.ode.ODEIntegrator
37 * @see ODEStateInterpolator
38 */
39
40 public interface ODEStepHandler {
41
42 /** Initialize step handler at the start of an ODE integration.
43 * <p>
44 * This method is called once at the start of the integration. It
45 * may be used by the step handler to initialize some internal data
46 * if needed.
47 * </p>
48 * <p>
49 * The default implementation does nothing
50 * </p>
51 * @param initialState initial time, state vector and derivative
52 * @param finalTime target time for the integration
53 */
54 default void init(ODEStateAndDerivative initialState, double finalTime) {
55 // nothing by default
56 }
57
58 /**
59 * Handle the last accepted step.
60 * @param interpolator interpolator for the last accepted step
61 */
62 void handleStep(ODEStateInterpolator interpolator);
63
64 /**
65 * Finalize integration.
66 * @param finalState state at integration end
67 * @since 2.0
68 */
69 default void finish(ODEStateAndDerivative finalState) {
70 // nothing by default
71 }
72
73 }