001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.math3.ode;
019
020import java.util.Collection;
021
022import org.apache.commons.math3.analysis.solvers.UnivariateSolver;
023import org.apache.commons.math3.ode.events.EventHandler;
024import org.apache.commons.math3.ode.sampling.StepHandler;
025
026/**
027 * This interface defines the common parts shared by integrators
028 * for first and second order differential equations.
029 * @see FirstOrderIntegrator
030 * @see SecondOrderIntegrator
031 * @version $Id: ODEIntegrator.java 1416643 2012-12-03 19:37:14Z tn $
032 * @since 2.0
033 */
034public interface ODEIntegrator  {
035
036    /** Get the name of the method.
037     * @return name of the method
038     */
039    String getName();
040
041    /** Add a step handler to this integrator.
042     * <p>The handler will be called by the integrator for each accepted
043     * step.</p>
044     * @param handler handler for the accepted steps
045     * @see #getStepHandlers()
046     * @see #clearStepHandlers()
047     * @since 2.0
048     */
049    void addStepHandler(StepHandler handler);
050
051    /** Get all the step handlers that have been added to the integrator.
052     * @return an unmodifiable collection of the added events handlers
053     * @see #addStepHandler(StepHandler)
054     * @see #clearStepHandlers()
055     * @since 2.0
056     */
057    Collection<StepHandler> getStepHandlers();
058
059    /** Remove all the step handlers that have been added to the integrator.
060     * @see #addStepHandler(StepHandler)
061     * @see #getStepHandlers()
062     * @since 2.0
063     */
064    void clearStepHandlers();
065
066    /** Add an event handler to the integrator.
067     * Uses a default {@link UnivariateSolver}
068     * with an absolute accuracy equal to the given convergence threshold,
069     * as root-finding algorithm to detect the state events.
070     * @param handler event handler
071     * @param maxCheckInterval maximal time interval between switching
072     * function checks (this interval prevents missing sign changes in
073     * case the integration steps becomes very large)
074     * @param convergence convergence threshold in the event time search
075     * @param maxIterationCount upper limit of the iteration count in
076     * the event time search
077     * @see #getEventHandlers()
078     * @see #clearEventHandlers()
079     */
080    void addEventHandler(EventHandler handler, double maxCheckInterval,
081                         double convergence, int maxIterationCount);
082
083    /** Add an event handler to the integrator.
084     * @param handler event handler
085     * @param maxCheckInterval maximal time interval between switching
086     * function checks (this interval prevents missing sign changes in
087     * case the integration steps becomes very large)
088     * @param convergence convergence threshold in the event time search
089     * @param maxIterationCount upper limit of the iteration count in
090     * the event time search
091     * @param solver The root-finding algorithm to use to detect the state
092     * events.
093     * @see #getEventHandlers()
094     * @see #clearEventHandlers()
095     */
096    void addEventHandler(EventHandler handler, double maxCheckInterval,
097                         double convergence, int maxIterationCount,
098                         UnivariateSolver solver);
099
100    /** Get all the event handlers that have been added to the integrator.
101     * @return an unmodifiable collection of the added events handlers
102     * @see #addEventHandler(EventHandler, double, double, int)
103     * @see #clearEventHandlers()
104     */
105    Collection<EventHandler> getEventHandlers();
106
107    /** Remove all the event handlers that have been added to the integrator.
108     * @see #addEventHandler(EventHandler, double, double, int)
109     * @see #getEventHandlers()
110     */
111    void clearEventHandlers();
112
113    /** Get the current value of the step start time t<sub>i</sub>.
114     * <p>This method can be called during integration (typically by
115     * the object implementing the {@link FirstOrderDifferentialEquations
116     * differential equations} problem) if the value of the current step that
117     * is attempted is needed.</p>
118     * <p>The result is undefined if the method is called outside of
119     * calls to <code>integrate</code>.</p>
120     * @return current value of the step start time t<sub>i</sub>
121     */
122    double getCurrentStepStart();
123
124    /** Get the current signed value of the integration stepsize.
125     * <p>This method can be called during integration (typically by
126     * the object implementing the {@link FirstOrderDifferentialEquations
127     * differential equations} problem) if the signed value of the current stepsize
128     * that is tried is needed.</p>
129     * <p>The result is undefined if the method is called outside of
130     * calls to <code>integrate</code>.</p>
131     * @return current signed value of the stepsize
132     */
133    double getCurrentSignedStepsize();
134
135    /** Set the maximal number of differential equations function evaluations.
136     * <p>The purpose of this method is to avoid infinite loops which can occur
137     * for example when stringent error constraints are set or when lots of
138     * discrete events are triggered, thus leading to many rejected steps.</p>
139     * @param maxEvaluations maximal number of function evaluations (negative
140     * values are silently converted to maximal integer value, thus representing
141     * almost unlimited evaluations)
142     */
143    void setMaxEvaluations(int maxEvaluations);
144
145    /** Get the maximal number of functions evaluations.
146     * @return maximal number of functions evaluations
147     */
148    int getMaxEvaluations();
149
150    /** Get the number of evaluations of the differential equations function.
151     * <p>
152     * The number of evaluations corresponds to the last call to the
153     * <code>integrate</code> method. It is 0 if the method has not been called yet.
154     * </p>
155     * @return number of evaluations of the differential equations function
156     */
157    int getEvaluations();
158
159}