    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
    018    package org.apache.commons.math.ode.sampling;
    019
    020    import org.apache.commons.math.ode.DerivativeException;
    021
    022    /**
    023     * This interface represents a handler that should be called after
    024     * each successful fixed step.
    025
    026     * <p>This interface should be implemented by anyone who is interested
    027     * in getting the solution of an ordinary differential equation at
    028     * fixed time steps. Objects implementing this interface should be
    029     * wrapped within an instance of {@link StepNormalizer} that itself
    030     * is used as the general {@link StepHandler} by the integrator. The
    031     * {@link StepNormalizer} object is called according to the integrator
    032     * internal algorithms and it calls objects implementing this
    033     * interface as necessary at fixed time steps.</p>
    034     *
    035     * @see StepHandler
    036     * @see StepNormalizer
    037     * @version $Revision: 1073158 $ $Date: 2011-02-21 22:46:52 +0100 (lun. 21 f??vr. 2011) $
    038     * @since 1.2
    039     */
    040
    041    public interface FixedStepHandler  {
    042
    043      /**
    044       * Handle the last accepted step
    045       * @param t time of the current step
    046       * @param y state vector at t. For efficiency purposes, the {@link
    047       * StepNormalizer} class reuses the same array on each call, so if
    048       * the instance wants to keep it across all calls (for example to
    049       * provide at the end of the integration a complete array of all
    050       * steps), it should build a local copy store this copy.
    051       * @param yDot derivatives of the state vector state vector at t.
    052       * For efficiency purposes, the {@link StepNormalizer} class reuses
    053       * the same array on each call, so if
    054       * the instance wants to keep it across all calls (for example to
    055       * provide at the end of the integration a complete array of all
    056       * steps), it should build a local copy store this copy.
    057       * @param isLast true if the step is the last one
    058       * @throws DerivativeException if some error condition is encountered
    059       */
    060      void handleStep(double t, double[] y, double[] yDot, boolean isLast) throws DerivativeException;
    061
    062    }