Commons Math example source code file (ComplexUtilsTest.java)

This example Commons Math source code file (ComplexUtilsTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Math tags/keywords

complex, complex, complexutilstest, complexutilstest, expecting, expecting, illegalargumentexception, illegalargumentexception, testcase

The Commons Math ComplexUtilsTest.java source code

/*
 * 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.math.complex;

import org.apache.commons.math.TestUtils;

import junit.framework.TestCase;

/**
 * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
 */
public class ComplexUtilsTest extends TestCase {

    private double inf = Double.POSITIVE_INFINITY;
    private double negInf = Double.NEGATIVE_INFINITY;
    private double nan = Double.NaN;
    private double pi = Math.PI;

    private Complex negInfInf = new Complex(negInf, inf);
    private Complex infNegInf = new Complex(inf, negInf);
    private Complex infInf = new Complex(inf, inf);
    private Complex negInfNegInf = new Complex(negInf, negInf);
    private Complex infNaN = new Complex(inf, nan);

    public void testPolar2Complex() {
        TestUtils.assertEquals(Complex.ONE,
                ComplexUtils.polar2Complex(1, 0), 10e-12);
        TestUtils.assertEquals(Complex.ZERO,
                ComplexUtils.polar2Complex(0, 1), 10e-12);
        TestUtils.assertEquals(Complex.ZERO,
                ComplexUtils.polar2Complex(0, -1), 10e-12);
        TestUtils.assertEquals(Complex.I,
                ComplexUtils.polar2Complex(1, pi/2), 10e-12);
        TestUtils.assertEquals(Complex.I.negate(),
                ComplexUtils.polar2Complex(1, -pi/2), 10e-12);
        double r = 0;
        for (int i = 0; i < 5; i++) {
          r += i;
          double theta = 0;
          for (int j =0; j < 20; j++) {
              theta += pi / 6;
              TestUtils.assertEquals(altPolar(r, theta),
                      ComplexUtils.polar2Complex(r, theta), 10e-12);
          }
          theta = -2 * pi;
          for (int j =0; j < 20; j++) {
              theta -= pi / 6;
              TestUtils.assertEquals(altPolar(r, theta),
                      ComplexUtils.polar2Complex(r, theta), 10e-12);
          }
        }
    }

    protected Complex altPolar(double r, double theta) {
        return Complex.I.multiply(new Complex(theta, 0)).exp().multiply(new Complex(r, 0));
    }

    public void testPolar2ComplexIllegalModulus() {
        try {
            ComplexUtils.polar2Complex(-1, 0);
            fail("Expecting IllegalArgumentException");
        } catch (IllegalArgumentException ex) {
            // expected
        }
    }

    public void testPolar2ComplexNaN() {
        TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(nan, 1));
        TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(1, nan));
        TestUtils.assertSame(Complex.NaN,
                ComplexUtils.polar2Complex(nan, nan));
    }

    public void testPolar2ComplexInf() {
        TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(1, inf));
        TestUtils.assertSame(Complex.NaN,
                ComplexUtils.polar2Complex(1, negInf));
        TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(inf, inf));
        TestUtils.assertSame(Complex.NaN,
                ComplexUtils.polar2Complex(inf, negInf));
        TestUtils.assertSame(infInf, ComplexUtils.polar2Complex(inf, pi/4));
        TestUtils.assertSame(infNaN, ComplexUtils.polar2Complex(inf, 0));
        TestUtils.assertSame(infNegInf, ComplexUtils.polar2Complex(inf, -pi/4));
        TestUtils.assertSame(negInfInf, ComplexUtils.polar2Complex(inf, 3*pi/4));
        TestUtils.assertSame(negInfNegInf, ComplexUtils.polar2Complex(inf, 5*pi/4));
    }

}