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.math.ode;
19
20 import org.apache.commons.math.ode.events.EventHandler;
21 import org.apache.commons.math.ode.sampling.StepHandler;
22
23 /** This interface represents a first order integrator for
24 * differential equations.
25
26 * <p>The classes which are devoted to solve first order differential
27 * equations should implement this interface. The problems which can
28 * be handled should implement the {@link
29 * FirstOrderDifferentialEquations} interface.</p>
30 *
31 * @see FirstOrderDifferentialEquations
32 * @see StepHandler
33 * @see EventHandler
34 * @version $Revision: 674820 $ $Date: 2008-07-08 09:37:09 -0400 (Tue, 08 Jul 2008) $
35 * @since 1.2
36 */
37
38 public interface FirstOrderIntegrator extends ODEIntegrator {
39
40 /** Integrate the differential equations up to the given time.
41 * <p>This method solves an Initial Value Problem (IVP).</p>
42 * <p>Since this method stores some internal state variables made
43 * available in its public interface during integration ({@link
44 * #getCurrentSignedStepsize()}), it is <em>not</em> thread-safe.</p>
45 * @param equations differential equations to integrate
46 * @param t0 initial time
47 * @param y0 initial value of the state vector at t0
48 * @param t target time for the integration
49 * (can be set to a value smaller than <code>t0</code> for backward integration)
50 * @param y placeholder where to put the state vector at each successful
51 * step (and hence at the end of integration), can be the same object as y0
52 * @return stop time, will be the same as target time if integration reached its
53 * target, but may be different if some {@link EventHandler} stops it at some point.
54 * @throws IntegratorException if the integrator cannot perform integration
55 * @throws DerivativeException this exception is propagated to the caller if
56 * the underlying user function triggers one
57 */
58 public double integrate (FirstOrderDifferentialEquations equations,
59 double t0, double[] y0,
60 double t, double[] y)
61 throws DerivativeException, IntegratorException;
62
63 }