Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.math3.ode.sampling; import org.apache.commons.math3.exception.MaxCountExceededException; /** * This interface represents a handler that should be called after * each successful step. * * <p>The ODE integrators compute the evolution of the state vector at * some grid points that depend on their own internal algorithm. Once * they have found a new grid point (possibly after having computed * several evaluation of the derivative at intermediate points), they * provide it to objects implementing this interface. These objects * typically either ignore the intermediate steps and wait for the * last one, store the points in an ephemeris, or forward them to * specialized processing or output methods.</p> * * @see org.apache.commons.math3.ode.FirstOrderIntegrator * @see org.apache.commons.math3.ode.SecondOrderIntegrator * @see StepInterpolator * @version $Id: StepHandler.java 1416643 2012-12-03 19:37:14Z tn $ * @since 1.2 */ public interface StepHandler { /** Initialize step handler at the start of an ODE integration. * <p> * This method is called once at the start of the integration. It * may be used by the step handler to initialize some internal data * if needed. * </p> * @param t0 start value of the independent <i>time</i> variable * @param y0 array containing the start value of the state vector * @param t target time for the integration */ void init(double t0, double[] y0, double t); /** * Handle the last accepted step * @param interpolator interpolator for the last accepted step. For * efficiency purposes, the various integrators reuse the same * object on each call, so if the instance wants to keep it across * all calls (for example to provide at the end of the integration a * continuous model valid throughout the integration range, as the * {@link org.apache.commons.math3.ode.ContinuousOutputModel * ContinuousOutputModel} class does), it should build a local copy * using the clone method of the interpolator and store this copy. * Keeping only a reference to the interpolator and reusing it will * result in unpredictable behavior (potentially crashing the application). * @param isLast true if the step is the last one * @exception MaxCountExceededException if the interpolator throws one because * the number of functions evaluations is exceeded */ void handleStep(StepInterpolator interpolator, boolean isLast) throws MaxCountExceededException; }