| /* |
| * 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.nonstiff; |
| |
| import org.apache.commons.math3.ode.FirstOrderDifferentialEquations; |
| import org.apache.commons.math3.ode.events.EventHandler; |
| |
| |
| public class StepProblem |
| implements FirstOrderDifferentialEquations, EventHandler { |
| |
| public StepProblem(double rateBefore, double rateAfter, |
| double switchTime) { |
| this.rateAfter = rateAfter; |
| this.switchTime = switchTime; |
| setRate(rateBefore); |
| } |
| |
| public void computeDerivatives(double t, double[] y, double[] yDot) { |
| yDot[0] = rate; |
| } |
| |
| public int getDimension() { |
| return 1; |
| } |
| |
| public void setRate(double rate) { |
| this.rate = rate; |
| } |
| |
| public void init(double t0, double[] y0, double t) { |
| } |
| |
| public Action eventOccurred(double t, double[] y, boolean increasing) { |
| setRate(rateAfter); |
| return Action.RESET_DERIVATIVES; |
| } |
| |
| public double g(double t, double[] y) { |
| return t - switchTime; |
| } |
| |
| public void resetState(double t, double[] y) { |
| } |
| |
| private double rate; |
| private double rateAfter; |
| private double switchTime; |
| |
| } |