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.events;
19
20 import org.hipparchus.CalculusFieldElement;
21 import org.hipparchus.exception.MathIllegalArgumentException;
22 import org.hipparchus.exception.MathIllegalStateException;
23 import org.hipparchus.ode.FieldODEStateAndDerivative;
24 import org.hipparchus.ode.sampling.FieldODEStateInterpolator;
25
26 /** This interface handles the state for either one {@link FieldODEEventHandler
27 * event handler} or one {@link FieldODEStepEndHandler step end handler}
28 * during integration steps.
29 * @since 3.0
30 * @param <T> the type of the field elements
31 */
32 public interface FieldEventState<T extends CalculusFieldElement<T>> {
33
34 /** Initialize handler at the start of an integration.
35 * <p>
36 * This method is called once at the start of the integration. It
37 * may be used by the event handler to initialize some internal data
38 * if needed.
39 * </p>
40 * @param s0 initial state
41 * @param t target time for the integration
42 *
43 */
44 void init(FieldODEStateAndDerivative<T> s0, T t);
45
46 /** Get the occurrence time of the event triggered in the current step.
47 * @return occurrence time of the event triggered in the current
48 * step or infinity if no events are triggered
49 */
50 T getEventTime();
51
52 /** Evaluate the impact of the proposed step on the event handler.
53 * @param interpolator step interpolator for the proposed step
54 * @return true if the event handler triggers an event before
55 * the end of the proposed step
56 * @exception MathIllegalStateException if the interpolator throws one because
57 * the number of functions evaluations is exceeded
58 * @exception MathIllegalArgumentException if the event cannot be bracketed
59 */
60 boolean evaluateStep(FieldODEStateInterpolator<T> interpolator)
61 throws MathIllegalArgumentException, MathIllegalStateException;
62
63 /**
64 * Notify the user's listener of the event. The event occurs wholly within this method
65 * call including a call to {@link FieldODEEventHandler#resetState(FieldODEEventDetector,
66 * FieldODEStateAndDerivative)} if necessary.
67 *
68 * @param state the state at the time of the event. This must be at the same time as
69 * the current value of {@link #getEventTime()}.
70 * @return the user's requested action and the new state if the action is {@link
71 * Action#RESET_STATE}. Otherwise the new state is {@code state}. The stop time
72 * indicates what time propagation should stop if the action is {@link Action#STOP}.
73 * This guarantees the integration will stop on or after the root, so that integration
74 * may be restarted safely.
75 */
76 FieldEventOccurrence<T> doEvent(FieldODEStateAndDerivative<T> state);
77
78 }