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 /** This interface represents a first order integrator for 021 * differential equations. 022 023 * <p>The classes which are devoted to solve first order differential 024 * equations should implement this interface. The problems which can 025 * be handled should implement the {@link 026 * FirstOrderDifferentialEquations} interface.</p> 027 * 028 * @see FirstOrderDifferentialEquations 029 * @see org.apache.commons.math.ode.sampling.StepHandler 030 * @see org.apache.commons.math.ode.events.EventHandler 031 * @version $Revision: 811786 $ $Date: 2009-09-06 05:36:08 -0400 (Sun, 06 Sep 2009) $ 032 * @since 1.2 033 */ 034 035 public interface FirstOrderIntegrator extends ODEIntegrator { 036 037 /** Integrate the differential equations up to the given time. 038 * <p>This method solves an Initial Value Problem (IVP).</p> 039 * <p>Since this method stores some internal state variables made 040 * available in its public interface during integration ({@link 041 * #getCurrentSignedStepsize()}), it is <em>not</em> thread-safe.</p> 042 * @param equations differential equations to integrate 043 * @param t0 initial time 044 * @param y0 initial value of the state vector at t0 045 * @param t target time for the integration 046 * (can be set to a value smaller than <code>t0</code> for backward integration) 047 * @param y placeholder where to put the state vector at each successful 048 * step (and hence at the end of integration), can be the same object as y0 049 * @return stop time, will be the same as target time if integration reached its 050 * target, but may be different if some {@link 051 * org.apache.commons.math.ode.events.EventHandler} stops it at some point. 052 * @throws IntegratorException if the integrator cannot perform integration 053 * @throws DerivativeException this exception is propagated to the caller if 054 * the underlying user function triggers one 055 */ 056 double integrate (FirstOrderDifferentialEquations equations, 057 double t0, double[] y0, 058 double t, double[] y) throws DerivativeException, IntegratorException; 059 060 }