| /* |
| * 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.math.ode; |
| |
| /** |
| * 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 FirstOrderIntegrator |
| * @see SecondOrderIntegrator |
| * @see StepInterpolator |
| * @version $Revision$ $Date$ |
| * @since 1.2 |
| */ |
| |
| public interface StepHandler { |
| |
| /** Determines whether this handler needs dense output. |
| * <p>This method allows the integrator to avoid performing extra |
| * computation if the handler does not need dense output. If this |
| * method returns false, the integrator will call the {@link |
| * #handleStep} method with a {@link DummyStepInterpolator} rather |
| * than a custom interpolator.</p> |
| * @return true if the handler needs dense output |
| */ |
| public boolean requiresDenseOutput(); |
| |
| /** Reset the step handler. |
| * Initialize the internal data as required before the first step is |
| * handled. |
| */ |
| public void reset(); |
| |
| /** |
| * 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 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 |
| * behaviour (potentially crashing the application). |
| * @param isLast true if the step is the last one |
| * @throws DerivativeException this exception is propagated to the |
| * caller if the underlying user function triggers one |
| */ |
| public void handleStep(StepInterpolator interpolator, boolean isLast) |
| throws DerivativeException; |
| |
| } |