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 }