/*
* 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;
/**
* This interface represents a handler that should be called after
* each successful fixed step.
* <p>This interface should be implemented by anyone who is interested
* in getting the solution of an ordinary differential equation at
* fixed time steps. Objects implementing this interface should be
* wrapped within an instance of {@link StepNormalizer} that itself
* is used as the general {@link StepHandler} by the integrator. The
* {@link StepNormalizer} object is called according to the integrator
* internal algorithms and it calls objects implementing this
* interface as necessary at fixed time steps.</p>
*
* @see StepHandler
* @see StepNormalizer
* @since 1.2
*/
public interface FixedStepHandler {
/** 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 t time of the current step
* @param y state vector at t. For efficiency purposes, the {@link
* StepNormalizer} class reuses the same array 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 complete array of all
* steps), it should build a local copy store this copy.
* @param yDot derivatives of the state vector state vector at t.
* For efficiency purposes, the {@link StepNormalizer} class reuses
* the same array 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 complete array of all
* steps), it should build a local copy store this copy.
* @param isLast true if the step is the last one
*/
void handleStep(double t, double[] y, double[] yDot, boolean isLast);
}