/*
* 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.events;
import org.apache.commons.math3.analysis.solvers.BracketingNthOrderBrentSolver;
import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.MaxCountExceededException;
import org.apache.commons.math3.exception.NoBracketingException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.ode.FirstOrderDifferentialEquations;
import org.apache.commons.math3.ode.FirstOrderIntegrator;
import org.apache.commons.math3.ode.nonstiff.DormandPrince853Integrator;
import org.apache.commons.math3.random.RandomGenerator;
import org.apache.commons.math3.random.Well19937a;
import org.apache.commons.math3.util.FastMath;
import org.junit.Assert;
import org.junit.Test;
public class EventFilterTest {
@Test
public void testHistoryIncreasingForward() {
// start point: g > 0
testHistory(FilterType.TRIGGER_ONLY_INCREASING_EVENTS,
0.5 * FastMath.PI, 30.5 * FastMath.PI, FastMath.PI, -1);
// start point: g = 0
testHistory(FilterType.TRIGGER_ONLY_INCREASING_EVENTS,
0, 30.5 * FastMath.PI, FastMath.PI, -1);
// start point: g < 0
testHistory(FilterType.TRIGGER_ONLY_INCREASING_EVENTS,
1.5 * FastMath.PI, 30.5 * FastMath.PI, FastMath.PI, +1);
}
@Test
public void testHistoryIncreasingBackward() {
// start point: g > 0
testHistory(FilterType.TRIGGER_ONLY_INCREASING_EVENTS,
0.5 * FastMath.PI, -30.5 * FastMath.PI, FastMath.PI, -1);
// start point: g = 0
testHistory(FilterType.TRIGGER_ONLY_INCREASING_EVENTS,
0, -30.5 * FastMath.PI, FastMath.PI, +1);
// start point: g < 0
testHistory(FilterType.TRIGGER_ONLY_INCREASING_EVENTS,
1.5 * FastMath.PI, -30.5 * FastMath.PI, FastMath.PI, -1);
}
@Test
public void testHistoryDecreasingForward() {
// start point: g > 0
testHistory(FilterType.TRIGGER_ONLY_DECREASING_EVENTS,
0.5 * FastMath.PI, 30.5 * FastMath.PI, 0, +1);
// start point: g = 0
testHistory(FilterType.TRIGGER_ONLY_DECREASING_EVENTS,
0, 30.5 * FastMath.PI, 0, +1);
// start point: g < 0
testHistory(FilterType.TRIGGER_ONLY_DECREASING_EVENTS,
1.5 * FastMath.PI, 30.5 * FastMath.PI, 0, +1);
}
@Test
public void testHistoryDecreasingBackward() {
// start point: g > 0
testHistory(FilterType.TRIGGER_ONLY_DECREASING_EVENTS,
0.5 * FastMath.PI, -30.5 * FastMath.PI, 0, -1);
// start point: g = 0
testHistory(FilterType.TRIGGER_ONLY_DECREASING_EVENTS,
0, -30.5 * FastMath.PI, 0, -1);
// start point: g < 0
testHistory(FilterType.TRIGGER_ONLY_DECREASING_EVENTS,
1.5 * FastMath.PI, -30.5 * FastMath.PI, 0, +1);
}
public void testHistory(FilterType type, double t0, double t1, double refSwitch, double signEven) {
Event onlyIncreasing = new Event(false, true);
EventFilter eventFilter =
new EventFilter(onlyIncreasing, type);
eventFilter.init(t0, new double[] {1.0, 0.0}, t1);
// first pass to set up switches history for a long period
double h = FastMath.copySign(0.05, t1 - t0);
double n = (int) FastMath.floor((t1 - t0) / h);
for (int i = 0; i < n; ++i) {
double t = t0 + i * h;
eventFilter.g(t, new double[] { FastMath.sin(t), FastMath.cos(t) });
}
// verify old events are preserved, even if randomly accessed
RandomGenerator rng = new Well19937a(0xb0e7401265af8cd3l);
for (int i = 0; i < 5000; i++) {
double t = t0 + (t1 - t0) * rng.nextDouble();
double g = eventFilter.g(t, new double[] { FastMath.sin(t), FastMath.cos(t) });
int turn = (int) FastMath.floor((t - refSwitch) / (2 * FastMath.PI));
if (turn % 2 == 0) {
Assert.assertEquals( signEven * FastMath.sin(t), g, 1.0e-10);
} else {
Assert.assertEquals(-signEven * FastMath.sin(t), g, 1.0e-10);
}
}
}
@Test
public void testIncreasingOnly()
throws DimensionMismatchException, NumberIsTooSmallException,
MaxCountExceededException, NoBracketingException {
double e = 1e-15;
FirstOrderIntegrator integrator;
integrator = new DormandPrince853Integrator(1.0e-3, 100.0, 1e-7, 1e-7);
Event allEvents = new Event(true, true);
integrator.addEventHandler(allEvents, 0.1, e, 1000,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
Event onlyIncreasing = new Event(false, true);
integrator.addEventHandler(new EventFilter(onlyIncreasing,
FilterType.TRIGGER_ONLY_INCREASING_EVENTS),
0.1, e, 100,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
double t0 = 0.5 * FastMath.PI;
double tEnd = 5.5 * FastMath.PI;
double[] y = { 0.0, 1.0 };
Assert.assertEquals(tEnd,
integrator.integrate(new SineCosine(), t0, y, tEnd, y),
1.0e-7);
Assert.assertEquals(5, allEvents.getEventCount());
Assert.assertEquals(2, onlyIncreasing.getEventCount());
}
@Test
public void testDecreasingOnly()
throws DimensionMismatchException, NumberIsTooSmallException,
MaxCountExceededException, NoBracketingException {
double e = 1e-15;
FirstOrderIntegrator integrator;
integrator = new DormandPrince853Integrator(1.0e-3, 100.0, 1e-7, 1e-7);
Event allEvents = new Event(true, true);
integrator.addEventHandler(allEvents, 0.1, e, 1000,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
Event onlyDecreasing = new Event(true, false);
integrator.addEventHandler(new EventFilter(onlyDecreasing,
FilterType.TRIGGER_ONLY_DECREASING_EVENTS),
0.1, e, 1000,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
double t0 = 0.5 * FastMath.PI;
double tEnd = 5.5 * FastMath.PI;
double[] y = { 0.0, 1.0 };
Assert.assertEquals(tEnd,
integrator.integrate(new SineCosine(), t0, y, tEnd, y),
1.0e-7);
Assert.assertEquals(5, allEvents.getEventCount());
Assert.assertEquals(3, onlyDecreasing.getEventCount());
}
@Test
public void testTwoOppositeFilters()
throws DimensionMismatchException, NumberIsTooSmallException,
MaxCountExceededException, NoBracketingException {
double e = 1e-15;
FirstOrderIntegrator integrator;
integrator = new DormandPrince853Integrator(1.0e-3, 100.0, 1e-7, 1e-7);
Event allEvents = new Event(true, true);
integrator.addEventHandler(allEvents, 0.1, e, 1000,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
Event onlyIncreasing = new Event(false, true);
integrator.addEventHandler(new EventFilter(onlyIncreasing,
FilterType.TRIGGER_ONLY_INCREASING_EVENTS),
0.1, e, 1000,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
Event onlyDecreasing = new Event(true, false);
integrator.addEventHandler(new EventFilter(onlyDecreasing,
FilterType.TRIGGER_ONLY_DECREASING_EVENTS),
0.1, e, 1000,
new BracketingNthOrderBrentSolver(1.0e-7, 5));
double t0 = 0.5 * FastMath.PI;
double tEnd = 5.5 * FastMath.PI;
double[] y = { 0.0, 1.0 };
Assert.assertEquals(tEnd,
integrator.integrate(new SineCosine(), t0, y, tEnd, y),
1.0e-7);
Assert.assertEquals(5, allEvents.getEventCount());
Assert.assertEquals(2, onlyIncreasing.getEventCount());
Assert.assertEquals(3, onlyDecreasing.getEventCount());
}
private static class SineCosine implements FirstOrderDifferentialEquations {
public int getDimension() {
return 2;
}
public void computeDerivatives(double t, double[] y, double[] yDot) {
yDot[0] = y[1];
yDot[1] = -y[0];
}
}
/** State events for this unit test. */
protected static class Event implements EventHandler {
private final boolean expectDecreasing;
private final boolean expectIncreasing;
private int eventCount;
public Event(boolean expectDecreasing, boolean expectIncreasing) {
this.expectDecreasing = expectDecreasing;
this.expectIncreasing = expectIncreasing;
}
public int getEventCount() {
return eventCount;
}
public void init(double t0, double[] y0, double t) {
eventCount = 0;
}
public double g(double t, double[] y) {
return y[0];
}
public Action eventOccurred(double t, double[] y, boolean increasing) {
if (increasing) {
Assert.assertTrue(expectIncreasing);
} else {
Assert.assertTrue(expectDecreasing);
}
eventCount++;
return Action.RESET_STATE;
}
public void resetState(double t, double[] y) {
// in fact, we don't really reset anything for this test
}
}
}