001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.math3.ode;
019
020 import java.io.Serializable;
021
022 import org.apache.commons.math3.exception.DimensionMismatchException;
023
024 /**
025 * Class mapping the part of a complete state or derivative that pertains
026 * to a specific differential equation.
027 * <p>
028 * Instances of this class are guaranteed to be immutable.
029 * </p>
030 * @see SecondaryEquations
031 * @version $Id: EquationsMapper.java 1416643 2012-12-03 19:37:14Z tn $
032 * @since 3.0
033 */
034 public class EquationsMapper implements Serializable {
035
036 /** Serializable UID. */
037 private static final long serialVersionUID = 20110925L;
038
039 /** Index of the first equation element in complete state arrays. */
040 private final int firstIndex;
041
042 /** Dimension of the secondary state parameters. */
043 private final int dimension;
044
045 /** simple constructor.
046 * @param firstIndex index of the first equation element in complete state arrays
047 * @param dimension dimension of the secondary state parameters
048 */
049 public EquationsMapper(final int firstIndex, final int dimension) {
050 this.firstIndex = firstIndex;
051 this.dimension = dimension;
052 }
053
054 /** Get the index of the first equation element in complete state arrays.
055 * @return index of the first equation element in complete state arrays
056 */
057 public int getFirstIndex() {
058 return firstIndex;
059 }
060
061 /** Get the dimension of the secondary state parameters.
062 * @return dimension of the secondary state parameters
063 */
064 public int getDimension() {
065 return dimension;
066 }
067
068 /** Extract equation data from a complete state or derivative array.
069 * @param complete complete state or derivative array from which
070 * equation data should be retrieved
071 * @param equationData placeholder where to put equation data
072 * @throws DimensionMismatchException if the dimension of the equation data does not
073 * match the mapper dimension
074 */
075 public void extractEquationData(double[] complete, double[] equationData)
076 throws DimensionMismatchException {
077 if (equationData.length != dimension) {
078 throw new DimensionMismatchException(equationData.length, dimension);
079 }
080 System.arraycopy(complete, firstIndex, equationData, 0, dimension);
081 }
082
083 /** Insert equation data into a complete state or derivative array.
084 * @param equationData equation data to be inserted into the complete array
085 * @param complete placeholder where to put equation data (only the
086 * part corresponding to the equation will be overwritten)
087 * @throws DimensionMismatchException if the dimension of the equation data does not
088 * match the mapper dimension
089 */
090 public void insertEquationData(double[] equationData, double[] complete)
091 throws DimensionMismatchException {
092 if (equationData.length != dimension) {
093 throw new DimensionMismatchException(equationData.length, dimension);
094 }
095 System.arraycopy(equationData, 0, complete, firstIndex, dimension);
096 }
097
098 }