/*
* 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.analysis.solvers;
import org.apache.commons.math4.analysis.QuinticFunction;
import org.apache.commons.math4.analysis.UnivariateFunction;
import org.apache.commons.math4.analysis.function.Sin;
import org.apache.commons.math4.analysis.solvers.UnivariateSolverUtils;
import org.apache.commons.math4.exception.MathIllegalArgumentException;
import org.apache.commons.math4.exception.NoBracketingException;
import org.apache.commons.math4.exception.NullArgumentException;
import org.apache.commons.math4.util.FastMath;
import org.junit.Assert;
import org.junit.Test;
/**
*/
public class UnivariateSolverUtilsTest {
protected UnivariateFunction sin = new Sin();
@Test(expected=NullArgumentException.class)
public void testSolveNull() {
UnivariateSolverUtils.solve(null, 0.0, 4.0);
}
@Test(expected=MathIllegalArgumentException.class)
public void testSolveBadEndpoints() {
double root = UnivariateSolverUtils.solve(sin, 4.0, -0.1, 1e-6);
System.out.println("root=" + root);
}
@Test
public void testSolveBadAccuracy() {
try { // bad accuracy
UnivariateSolverUtils.solve(sin, 0.0, 4.0, 0.0);
// Assert.fail("Expecting MathIllegalArgumentException"); // TODO needs rework since convergence behaviour was changed
} catch (MathIllegalArgumentException ex) {
// expected
}
}
@Test
public void testSolveSin() {
double x = UnivariateSolverUtils.solve(sin, 1.0, 4.0);
Assert.assertEquals(FastMath.PI, x, 1.0e-4);
}
@Test(expected=NullArgumentException.class)
public void testSolveAccuracyNull() {
double accuracy = 1.0e-6;
UnivariateSolverUtils.solve(null, 0.0, 4.0, accuracy);
}
@Test
public void testSolveAccuracySin() {
double accuracy = 1.0e-6;
double x = UnivariateSolverUtils.solve(sin, 1.0,
4.0, accuracy);
Assert.assertEquals(FastMath.PI, x, accuracy);
}
@Test(expected=MathIllegalArgumentException.class)
public void testSolveNoRoot() {
UnivariateSolverUtils.solve(sin, 1.0, 1.5);
}
@Test
public void testBracketSin() {
double[] result = UnivariateSolverUtils.bracket(sin,
0.0, -2.0, 2.0);
Assert.assertTrue(sin.value(result[0]) < 0);
Assert.assertTrue(sin.value(result[1]) > 0);
}
@Test
public void testBracketCentered() {
double initial = 0.1;
double[] result = UnivariateSolverUtils.bracket(sin, initial, -2.0, 2.0, 0.2, 1.0, 100);
Assert.assertTrue(result[0] < initial);
Assert.assertTrue(result[1] > initial);
Assert.assertTrue(sin.value(result[0]) < 0);
Assert.assertTrue(sin.value(result[1]) > 0);
}
@Test
public void testBracketLow() {
double initial = 0.5;
double[] result = UnivariateSolverUtils.bracket(sin, initial, -2.0, 2.0, 0.2, 1.0, 100);
Assert.assertTrue(result[0] < initial);
Assert.assertTrue(result[1] < initial);
Assert.assertTrue(sin.value(result[0]) < 0);
Assert.assertTrue(sin.value(result[1]) > 0);
}
@Test
public void testBracketHigh(){
double initial = -0.5;
double[] result = UnivariateSolverUtils.bracket(sin, initial, -2.0, 2.0, 0.2, 1.0, 100);
Assert.assertTrue(result[0] > initial);
Assert.assertTrue(result[1] > initial);
Assert.assertTrue(sin.value(result[0]) < 0);
Assert.assertTrue(sin.value(result[1]) > 0);
}
@Test(expected=NoBracketingException.class)
public void testBracketLinear(){
UnivariateSolverUtils.bracket(new UnivariateFunction() {
@Override
public double value(double x) {
return 1 - x;
}
}, 1000, Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, 1.0, 1.0, 100);
}
@Test
public void testBracketExponential(){
double[] result = UnivariateSolverUtils.bracket(new UnivariateFunction() {
@Override
public double value(double x) {
return 1 - x;
}
}, 1000, Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, 1.0, 2.0, 10);
Assert.assertTrue(result[0] <= 1);
Assert.assertTrue(result[1] >= 1);
}
@Test
public void testBracketEndpointRoot() {
double[] result = UnivariateSolverUtils.bracket(sin, 1.5, 0, 2.0);
Assert.assertEquals(0.0, sin.value(result[0]), 1.0e-15);
Assert.assertTrue(sin.value(result[1]) > 0);
}
@Test(expected=NullArgumentException.class)
public void testNullFunction() {
UnivariateSolverUtils.bracket(null, 1.5, 0, 2.0);
}
@Test(expected=MathIllegalArgumentException.class)
public void testBadInitial() {
UnivariateSolverUtils.bracket(sin, 2.5, 0, 2.0);
}
@Test(expected=MathIllegalArgumentException.class)
public void testBadAdditive() {
UnivariateSolverUtils.bracket(sin, 1.0, -2.0, 3.0, -1.0, 1.0, 100);
}
@Test(expected=NoBracketingException.class)
public void testIterationExceeded() {
UnivariateSolverUtils.bracket(sin, 1.0, -2.0, 3.0, 1.0e-5, 1.0, 100);
}
@Test(expected=MathIllegalArgumentException.class)
public void testBadEndpoints() {
// endpoints not valid
UnivariateSolverUtils.bracket(sin, 1.5, 2.0, 1.0);
}
@Test(expected=MathIllegalArgumentException.class)
public void testBadMaximumIterations() {
// bad maximum iterations
UnivariateSolverUtils.bracket(sin, 1.5, 0, 2.0, 0);
}
/** check the search continues when a = lowerBound and b < upperBound. */
@Test
public void testBracketLoopConditionForB() {
double[] result = UnivariateSolverUtils.bracket(sin, -0.9, -1, 1, 0.1, 1, 100);
Assert.assertTrue(result[0] <= 0);
Assert.assertTrue(result[1] >= 0);
}
@Test
public void testMisc() {
UnivariateFunction f = new QuinticFunction();
double result;
// Static solve method
result = UnivariateSolverUtils.solve(f, -0.2, 0.2);
Assert.assertEquals(result, 0, 1E-8);
result = UnivariateSolverUtils.solve(f, -0.1, 0.3);
Assert.assertEquals(result, 0, 1E-8);
result = UnivariateSolverUtils.solve(f, -0.3, 0.45);
Assert.assertEquals(result, 0, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.3, 0.7);
Assert.assertEquals(result, 0.5, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.2, 0.6);
Assert.assertEquals(result, 0.5, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.05, 0.95);
Assert.assertEquals(result, 0.5, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.85, 1.25);
Assert.assertEquals(result, 1.0, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.8, 1.2);
Assert.assertEquals(result, 1.0, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.85, 1.75);
Assert.assertEquals(result, 1.0, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.55, 1.45);
Assert.assertEquals(result, 1.0, 1E-6);
result = UnivariateSolverUtils.solve(f, 0.85, 5);
Assert.assertEquals(result, 1.0, 1E-6);
}
}