| /* |
| * 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.math4.legacy.ode.events; |
| |
| import org.apache.commons.math4.legacy.ode.FirstOrderDifferentialEquations; |
| import org.apache.commons.math4.legacy.ode.FirstOrderIntegrator; |
| import org.apache.commons.math4.legacy.ode.nonstiff.DormandPrince853Integrator; |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| /** |
| * Check events are detected correctly when the event times are close. |
| * |
| * @author Evan Ward |
| */ |
| public class CloseEventsTest { |
| |
| @Test |
| public void testCloseEvents() { |
| // setup |
| double e = 1e-15; |
| FirstOrderIntegrator integrator = |
| new DormandPrince853Integrator(e, 100.0, 1e-7, 1e-7); |
| |
| TimeDetector detector1 = new TimeDetector(5); |
| integrator.addEventHandler(detector1, 10, 1, 100); |
| TimeDetector detector2 = new TimeDetector(5.5); |
| integrator.addEventHandler(detector2, 10, 1, 100); |
| |
| // action |
| integrator.integrate(new Equation(), 0, new double[2], 20, new double[2]); |
| |
| // verify |
| Assert.assertEquals(5, detector1.getActualT(), 0.0); |
| Assert.assertEquals(5.5, detector2.getActualT(), 0.0); |
| } |
| |
| @Test |
| public void testSimultaneousEvents() { |
| // setup |
| double e = 1e-15; |
| FirstOrderIntegrator integrator = |
| new DormandPrince853Integrator(e, 100.0, 1e-7, 1e-7); |
| |
| TimeDetector detector1 = new TimeDetector(5); |
| integrator.addEventHandler(detector1, 10, 1, 100); |
| TimeDetector detector2 = new TimeDetector(5); |
| integrator.addEventHandler(detector2, 10, 1, 100); |
| |
| // action |
| integrator.integrate(new Equation(), 0, new double[2], 20, new double[2]); |
| |
| // verify |
| Assert.assertEquals(5, detector1.getActualT(), 0.0); |
| Assert.assertEquals(5, detector2.getActualT(), 0.0); |
| } |
| |
| |
| /** Trigger an event at a particular time. */ |
| private static class TimeDetector implements EventHandler { |
| |
| /** time of the event to trigger. */ |
| private final double eventT; |
| |
| /** time the event was actually triggered. */ |
| private double actualT; |
| |
| /** |
| * Create a new detector. |
| * |
| * @param eventT the time to trigger an event. |
| */ |
| TimeDetector(double eventT) { |
| this.eventT = eventT; |
| } |
| |
| /** Get the actual time the event occurred. */ |
| public double getActualT() { |
| return actualT; |
| } |
| |
| @Override |
| public void init(double t0, double[] y0, double t) { |
| } |
| |
| @Override |
| public double g(double t, double[] y) { |
| return t - eventT; |
| } |
| |
| @Override |
| public Action eventOccurred(double t, double[] y, boolean increasing) { |
| this.actualT = t; |
| return Action.CONTINUE; |
| } |
| |
| @Override |
| public void resetState(double t, double[] y) { |
| } |
| |
| } |
| |
| /** Some basic equations to integrate. */ |
| public static class Equation implements FirstOrderDifferentialEquations { |
| |
| @Override |
| public int getDimension() { |
| return 2; |
| } |
| |
| @Override |
| public void computeDerivatives(double t, double[] y, double[] yDot) { |
| yDot[0] = 1.0; |
| yDot[1] = 2.0; |
| } |
| |
| } |
| |
| } |