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 * https://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 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22
23 package org.hipparchus.migration.ode;
24
25 import org.hipparchus.exception.MathIllegalArgumentException;
26 import org.hipparchus.exception.MathIllegalStateException;
27 import org.hipparchus.ode.OrdinaryDifferentialEquation;
28
29
30
31 /** This interface represents a first order differential equations set.
32 *
33 * <p>This interface should be implemented by all real first order
34 * differential equation problems before they can be handled by the
35 * integrators {@link org.hipparchus.ode.ODEIntegrator#integrate} method.</p>
36 *
37 * <p>A first order differential equations problem, as seen by an
38 * integrator is the time derivative <code>dY/dt</code> of a state
39 * vector <code>Y</code>, both being one dimensional arrays. From the
40 * integrator point of view, this derivative depends only on the
41 * current time <code>t</code> and on the state vector
42 * <code>Y</code>.</p>
43 *
44 * <p>For real problems, the derivative depends also on parameters
45 * that do not belong to the state vector (dynamical model constants
46 * for example). These constants are completely outside of the scope
47 * of this interface, the classes that implement it are allowed to
48 * handle them as they want.</p>
49 *
50 * @see org.hipparchus.ode.ODEIntegrator
51 * @see org.hipparchus.ode.FirstOrderConverter
52 * @see SecondOrderDifferentialEquations
53 * @deprecated as of 1.0, replaced with {@link OrdinaryDifferentialEquation}
54 */
55 @Deprecated
56 public interface FirstOrderDifferentialEquations extends OrdinaryDifferentialEquation {
57
58 /** {@inheritDoc}
59 * <p>
60 * The default implementation calls {@link #computeDerivatives(double, double[], double[])}.
61 * </p>
62 */
63 @Override
64 default double[] computeDerivatives(double t, double[] y) {
65 final double[] yDot = new double[y.length];
66 computeDerivatives(t, y, yDot);
67 return yDot;
68 }
69
70 /** Get the current time derivative of the state vector.
71 * @param t current value of the independent <I>time</I> variable
72 * @param y array containing the current value of the state vector
73 * @param yDot placeholder array where to put the time derivative of the state vector
74 * @exception MathIllegalStateException if the number of functions evaluations is exceeded
75 * @exception MathIllegalArgumentException if arrays dimensions do not match equations settings
76 */
77 void computeDerivatives(double t, double[] y, double[] yDot)
78 throws MathIllegalArgumentException, MathIllegalStateException;
79
80 }