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.math4.legacy.ode;
19
20 import org.apache.commons.math4.legacy.core.RealFieldElement;
21
22 /** Container for time, main and secondary state vectors as well as their derivatives.
23
24 * @see FirstOrderFieldDifferentialEquations
25 * @see FieldSecondaryEquations
26 * @see FirstOrderFieldIntegrator
27 * @param <T> the type of the field elements
28 * @since 3.6
29 */
30
31 public class FieldODEStateAndDerivative<T extends RealFieldElement<T>> extends FieldODEState<T> {
32
33 /** Derivative of the main state at time. */
34 private final T[] derivative;
35
36 /** Derivative of the secondary state at time. */
37 private final T[][] secondaryDerivative;
38
39 /** Simple constructor.
40 * <p>Calling this constructor is equivalent to call {@link
41 * #FieldODEStateAndDerivative(RealFieldElement, RealFieldElement[], RealFieldElement[],
42 * RealFieldElement[][], RealFieldElement[][]) FieldODEStateAndDerivative(time, state,
43 * derivative, null, null)}.</p>
44 * @param time time
45 * @param state state at time
46 * @param derivative derivative of the state at time
47 */
48 public FieldODEStateAndDerivative(T time, T[] state, T[] derivative) {
49 this(time, state, derivative, null, null);
50 }
51
52 /** Simple constructor.
53 * @param time time
54 * @param state state at time
55 * @param derivative derivative of the state at time
56 * @param secondaryState state at time (may be null)
57 * @param secondaryDerivative derivative of the state at time (may be null)
58 */
59 public FieldODEStateAndDerivative(T time, T[] state, T[] derivative, T[][] secondaryState, T[][] secondaryDerivative) {
60 super(time, state, secondaryState);
61 this.derivative = derivative.clone();
62 this.secondaryDerivative = copy(time.getField(), secondaryDerivative);
63 }
64
65 /** Get derivative of the main state at time.
66 * @return derivative of the main state at time
67 */
68 public T[] getDerivative() {
69 return derivative.clone();
70 }
71
72 /** Get derivative of the secondary state at time.
73 * @param index index of the secondary set as returned
74 * by {@link FieldExpandableODE#addSecondaryEquations(FieldSecondaryEquations)}
75 * (beware index 0 corresponds to main state, additional states start at 1)
76 * @return derivative of the secondary state at time
77 */
78 public T[] getSecondaryDerivative(final int index) {
79 return index == 0 ? derivative.clone() : secondaryDerivative[index - 1].clone();
80 }
81 }