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 package org.apache.commons.math.ode; 18 19 20 /** This interface represents a first order differential equations set 21 * with a main set of equations and an extension set. 22 * 23 * <p> 24 * This interface is a simple extension on the {@link 25 * FirstOrderDifferentialEquations} that allows to identify which part 26 * of a complete set of differential equations correspond to the main 27 * set and which part correspond to the extension set. 28 * </p> 29 * <p> 30 * One typical use case is the computation of Jacobians. The main 31 * set of equations correspond to the raw ode, and we add to this set 32 * another bunch of equations which represent the jacobians of the 33 * main set. In that case, we want the integrator to use <em>only</em> 34 * the main set to estimate the errors and hence the step sizes. It should 35 * <em>not</em> use the additional equations in this computation. If the 36 * complete ode implements this interface, the {@link FirstOrderIntegrator 37 * integrator} will be able to know where the main set ends and where the 38 * extended set begins. 39 * </p> 40 * <p> 41 * We consider that the main set always corresponds to the first equations 42 * and the extended set to the last equations. 43 * </p> 44 * 45 * @see FirstOrderDifferentialEquations 46 * 47 * @version $Revision: 980981 $ $Date: 2010-07-31 00:03:04 +0200 (sam. 31 juil. 2010) $ 48 * @since 2.2 49 */ 50 51 public interface ExtendedFirstOrderDifferentialEquations extends FirstOrderDifferentialEquations { 52 53 /** Return the dimension of the main set of equations. 54 * <p> 55 * The main set of equations represent the first part of an ODE state. 56 * The error estimations and adaptive step size computation should be 57 * done on this first part only, not on the final part of the state 58 * which represent an extension set of equations which are considered 59 * secondary. 60 * </p> 61 * @return dimension of the main set of equations, must be lesser than or 62 * equal to the {@link #getDimension() total dimension} 63 */ getMainSetDimension()64 int getMainSetDimension(); 65 66 } 67