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 018package org.apache.commons.math3.ode; 019 020import java.io.Serializable; 021 022import 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 * @since 3.0 032 */ 033public class EquationsMapper implements Serializable { 034 035 /** Serializable UID. */ 036 private static final long serialVersionUID = 20110925L; 037 038 /** Index of the first equation element in complete state arrays. */ 039 private final int firstIndex; 040 041 /** Dimension of the secondary state parameters. */ 042 private final int dimension; 043 044 /** simple constructor. 045 * @param firstIndex index of the first equation element in complete state arrays 046 * @param dimension dimension of the secondary state parameters 047 */ 048 public EquationsMapper(final int firstIndex, final int dimension) { 049 this.firstIndex = firstIndex; 050 this.dimension = dimension; 051 } 052 053 /** Get the index of the first equation element in complete state arrays. 054 * @return index of the first equation element in complete state arrays 055 */ 056 public int getFirstIndex() { 057 return firstIndex; 058 } 059 060 /** Get the dimension of the secondary state parameters. 061 * @return dimension of the secondary state parameters 062 */ 063 public int getDimension() { 064 return dimension; 065 } 066 067 /** Extract equation data from a complete state or derivative array. 068 * @param complete complete state or derivative array from which 069 * equation data should be retrieved 070 * @param equationData placeholder where to put equation data 071 * @throws DimensionMismatchException if the dimension of the equation data does not 072 * match the mapper dimension 073 */ 074 public void extractEquationData(double[] complete, double[] equationData) 075 throws DimensionMismatchException { 076 if (equationData.length != dimension) { 077 throw new DimensionMismatchException(equationData.length, dimension); 078 } 079 System.arraycopy(complete, firstIndex, equationData, 0, dimension); 080 } 081 082 /** Insert equation data into a complete state or derivative array. 083 * @param equationData equation data to be inserted into the complete array 084 * @param complete placeholder where to put equation data (only the 085 * part corresponding to the equation will be overwritten) 086 * @throws DimensionMismatchException if the dimension of the equation data does not 087 * match the mapper dimension 088 */ 089 public void insertEquationData(double[] equationData, double[] complete) 090 throws DimensionMismatchException { 091 if (equationData.length != dimension) { 092 throw new DimensionMismatchException(equationData.length, dimension); 093 } 094 System.arraycopy(equationData, 0, complete, firstIndex, dimension); 095 } 096 097}