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
18package org.apache.commons.math.ode;
19
20
21/** This interface represents a first order integrator for
22 * differential equations.
23
24 * <p>The classes which are devoted to solve first order differential
25 * equations should implement this interface. The problems which can
26 * be handled should implement the {@link
27 * FirstOrderDifferentialEquations} interface.</p>
28 *
29 * @see FirstOrderDifferentialEquations
30 * @see org.apache.commons.math.ode.sampling.StepHandler
31 * @see org.apache.commons.math.ode.events.EventHandler
32 * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 févr. 2011) $
33 * @since 1.2
34 */
35
36public interface FirstOrderIntegrator extends ODEIntegrator {
37
38  /** Integrate the differential equations up to the given time.
39   * <p>This method solves an Initial Value Problem (IVP).</p>
40   * <p>Since this method stores some internal state variables made
41   * available in its public interface during integration ({@link
42   * #getCurrentSignedStepsize()}), it is <em>not</em> thread-safe.</p>
43   * @param equations differential equations to integrate
44   * @param t0 initial time
45   * @param y0 initial value of the state vector at t0
46   * @param t target time for the integration
47   * (can be set to a value smaller than <code>t0</code> for backward integration)
48   * @param y placeholder where to put the state vector at each successful
49   *  step (and hence at the end of integration), can be the same object as y0
50   * @return stop time, will be the same as target time if integration reached its
51   * target, but may be different if some {@link
52   * org.apache.commons.math.ode.events.EventHandler} stops it at some point.
53   * @throws DerivativeException this exception is propagated to the caller if
54   * the underlying user function triggers one
55   * @throws IntegratorException if the integrator cannot perform integration
56   */
57  double integrate (FirstOrderDifferentialEquations equations,
58                    double t0, double[] y0,
59                    double t, double[] y) throws DerivativeException, IntegratorException;
60
61}
62