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; 019 020 import org.apache.commons.math.ode.events.EventHandler; 021 import org.apache.commons.math.ode.sampling.StepHandler; 022 023 /** This interface represents a first order integrator for 024 * differential equations. 025 026 * <p>The classes which are devoted to solve first order differential 027 * equations should implement this interface. The problems which can 028 * be handled should implement the {@link 029 * FirstOrderDifferentialEquations} interface.</p> 030 * 031 * @see FirstOrderDifferentialEquations 032 * @see StepHandler 033 * @see EventHandler 034 * @version $Revision: 674820 $ $Date: 2008-07-08 09:37:09 -0400 (Tue, 08 Jul 2008) $ 035 * @since 1.2 036 */ 037 038 public interface FirstOrderIntegrator extends ODEIntegrator { 039 040 /** Integrate the differential equations up to the given time. 041 * <p>This method solves an Initial Value Problem (IVP).</p> 042 * <p>Since this method stores some internal state variables made 043 * available in its public interface during integration ({@link 044 * #getCurrentSignedStepsize()}), it is <em>not</em> thread-safe.</p> 045 * @param equations differential equations to integrate 046 * @param t0 initial time 047 * @param y0 initial value of the state vector at t0 048 * @param t target time for the integration 049 * (can be set to a value smaller than <code>t0</code> for backward integration) 050 * @param y placeholder where to put the state vector at each successful 051 * step (and hence at the end of integration), can be the same object as y0 052 * @return stop time, will be the same as target time if integration reached its 053 * target, but may be different if some {@link EventHandler} stops it at some point. 054 * @throws IntegratorException if the integrator cannot perform integration 055 * @throws DerivativeException this exception is propagated to the caller if 056 * the underlying user function triggers one 057 */ 058 public double integrate (FirstOrderDifferentialEquations equations, 059 double t0, double[] y0, 060 double t, double[] y) 061 throws DerivativeException, IntegratorException; 062 063 }