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.sampling; 019 020import org.apache.commons.math3.RealFieldElement; 021import org.apache.commons.math3.ode.FieldODEStateAndDerivative; 022 023/** 024 * This interface represents a handler that should be called after 025 * each successful fixed step. 026 027 * <p>This interface should be implemented by anyone who is interested 028 * in getting the solution of an ordinary differential equation at 029 * fixed time steps. Objects implementing this interface should be 030 * wrapped within an instance of {@link FieldStepNormalizer} that itself 031 * is used as the general {@link FieldStepHandler} by the integrator. The 032 * {@link FieldStepNormalizer} object is called according to the integrator 033 * internal algorithms and it calls objects implementing this 034 * interface as necessary at fixed time steps.</p> 035 * 036 * @see FieldStepHandler 037 * @see FieldStepNormalizer 038 * @see FieldStepInterpolator 039 * @param <T> the type of the field elements 040 * @since 3.6 041 */ 042 043public interface FieldFixedStepHandler<T extends RealFieldElement<T>> { 044 045 /** Initialize step handler at the start of an ODE integration. 046 * <p> 047 * This method is called once at the start of the integration. It 048 * may be used by the step handler to initialize some internal data 049 * if needed. 050 * </p> 051 * @param initialState initial time, state vector and derivative 052 * @param finalTime target time for the integration 053 */ 054 void init(FieldODEStateAndDerivative<T> initialState, T finalTime); 055 056 /** 057 * Handle the last accepted step 058 * @param state current value of the independent <i>time</i> variable, 059 * state vector and derivative 060 * For efficiency purposes, the {@link FieldStepNormalizer} class reuses 061 * the same array on each call, so if 062 * the instance wants to keep it across all calls (for example to 063 * provide at the end of the integration a complete array of all 064 * steps), it should build a local copy store this copy. 065 * @param isLast true if the step is the last one 066 */ 067 void handleStep(FieldODEStateAndDerivative<T> state, boolean isLast); 068 069}