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 org.apache.commons.math4.legacy.exception.DimensionMismatchException;
21 import org.apache.commons.math4.legacy.exception.MaxCountExceededException;
22
23 /**
24 * This interface allows users to add secondary differential equations to a primary
25 * set of differential equations.
26 * <p>
27 * In some cases users may need to integrate some problem-specific equations along
28 * with a primary set of differential equations. One example is optimal control where
29 * adjoined parameters linked to the minimized hamiltonian must be integrated.
30 * </p>
31 * <p>
32 * This interface allows users to add such equations to a primary set of {@link
33 * FirstOrderDifferentialEquations first order differential equations}
34 * thanks to the {@link
35 * ExpandableStatefulODE#addSecondaryEquations(SecondaryEquations)}
36 * method.
37 * </p>
38 * @see ExpandableStatefulODE
39 * @since 3.0
40 */
41 public interface SecondaryEquations {
42
43 /** Get the dimension of the secondary state parameters.
44 * @return dimension of the secondary state parameters
45 */
46 int getDimension();
47
48 /** Compute the derivatives related to the secondary state parameters.
49 * @param t current value of the independent <I>time</I> variable
50 * @param primary array containing the current value of the primary state vector
51 * @param primaryDot array containing the derivative of the primary state vector
52 * @param secondary array containing the current value of the secondary state vector
53 * @param secondaryDot placeholder array where to put the derivative of the secondary state vector
54 * @exception MaxCountExceededException if the number of functions evaluations is exceeded
55 * @exception DimensionMismatchException if arrays dimensions do not match equations settings
56 */
57 void computeDerivatives(double t, double[] primary, double[] primaryDot,
58 double[] secondary, double[] secondaryDot)
59 throws MaxCountExceededException, DimensionMismatchException;
60 }