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 import org.apache.commons.math4.legacy.exception.NoBracketingException;
23 import org.apache.commons.math4.legacy.exception.NumberIsTooSmallException;
24
25 /** This interface represents a first order integrator for
26 * differential equations.
27
28 * <p>The classes which are devoted to solve first order differential
29 * equations should implement this interface. The problems which can
30 * be handled should implement the {@link
31 * FirstOrderDifferentialEquations} interface.</p>
32 *
33 * @see FirstOrderDifferentialEquations
34 * @see org.apache.commons.math4.legacy.ode.sampling.StepHandler
35 * @see org.apache.commons.math4.legacy.ode.events.EventHandler
36 * @since 1.2
37 */
38
39 public interface FirstOrderIntegrator extends ODEIntegrator {
40
41 /** Integrate the differential equations up to the given time.
42 * <p>This method solves an Initial Value Problem (IVP).</p>
43 * <p>Since this method stores some internal state variables made
44 * available in its public interface during integration ({@link
45 * #getCurrentSignedStepsize()}), it is <em>not</em> thread-safe.</p>
46 * @param equations differential equations to integrate
47 * @param t0 initial time
48 * @param y0 initial value of the state vector at t0
49 * @param t target time for the integration
50 * (can be set to a value smaller than <code>t0</code> for backward integration)
51 * @param y placeholder where to put the state vector at each successful
52 * step (and hence at the end of integration), can be the same object as y0
53 * @return stop time, will be the same as target time if integration reached its
54 * target, but may be different if some {@link
55 * org.apache.commons.math4.legacy.ode.events.EventHandler} stops it at some point.
56 * @exception DimensionMismatchException if arrays dimension do not match equations settings
57 * @exception NumberIsTooSmallException if integration step is too small
58 * @exception MaxCountExceededException if the number of functions evaluations is exceeded
59 * @exception NoBracketingException if the location of an event cannot be bracketed
60 */
61 double integrate (FirstOrderDifferentialEquations equations,
62 double t0, double[] y0, double t, double[] y)
63 throws DimensionMismatchException, NumberIsTooSmallException,
64 MaxCountExceededException, NoBracketingException;
65 }