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 java.io.Serializable;
21
22 import org.apache.commons.math4.legacy.exception.DimensionMismatchException;
23
24 /**
25 * Class mapping the part of a complete state or derivative that pertains
26 * to a specific differential equation.
27 * <p>
28 * Instances of this class are guaranteed to be immutable.
29 * </p>
30 * @see SecondaryEquations
31 * @since 3.0
32 */
33 public class EquationsMapper implements Serializable {
34
35 /** Serializable UID. */
36 private static final long serialVersionUID = 20110925L;
37
38 /** Index of the first equation element in complete state arrays. */
39 private final int firstIndex;
40
41 /** Dimension of the secondary state parameters. */
42 private final int dimension;
43
44 /** simple constructor.
45 * @param firstIndex index of the first equation element in complete state arrays
46 * @param dimension dimension of the secondary state parameters
47 */
48 public EquationsMapper(final int firstIndex, final int dimension) {
49 this.firstIndex = firstIndex;
50 this.dimension = dimension;
51 }
52
53 /** Get the index of the first equation element in complete state arrays.
54 * @return index of the first equation element in complete state arrays
55 */
56 public int getFirstIndex() {
57 return firstIndex;
58 }
59
60 /** Get the dimension of the secondary state parameters.
61 * @return dimension of the secondary state parameters
62 */
63 public int getDimension() {
64 return dimension;
65 }
66
67 /** Extract equation data from a complete state or derivative array.
68 * @param complete complete state or derivative array from which
69 * equation data should be retrieved
70 * @param equationData placeholder where to put equation data
71 * @throws DimensionMismatchException if the dimension of the equation data does not
72 * match the mapper dimension
73 */
74 public void extractEquationData(double[] complete, double[] equationData)
75 throws DimensionMismatchException {
76 if (equationData.length != dimension) {
77 throw new DimensionMismatchException(equationData.length, dimension);
78 }
79 System.arraycopy(complete, firstIndex, equationData, 0, dimension);
80 }
81
82 /** Insert equation data into a complete state or derivative array.
83 * @param equationData equation data to be inserted into the complete array
84 * @param complete placeholder where to put equation data (only the
85 * part corresponding to the equation will be overwritten)
86 * @throws DimensionMismatchException if the dimension of the equation data does not
87 * match the mapper dimension
88 */
89 public void insertEquationData(double[] equationData, double[] complete)
90 throws DimensionMismatchException {
91 if (equationData.length != dimension) {
92 throw new DimensionMismatchException(equationData.length, dimension);
93 }
94 System.arraycopy(equationData, 0, complete, firstIndex, dimension);
95 }
96 }