1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.math.complex;
19  
20  import org.apache.commons.math.TestUtils;
21  
22  import junit.framework.TestCase;
23  
24  /**
25   * @version $Revision: 670469 $ $Date: 2008-06-23 04:01:38 -0400 (Mon, 23 Jun 2008) $
26   */
27  public class ComplexUtilsTest extends TestCase {
28      
29      private double inf = Double.POSITIVE_INFINITY;
30      private double negInf = Double.NEGATIVE_INFINITY;
31      private double nan = Double.NaN;
32      private double pi = Math.PI;
33      
34      private Complex negInfInf = new Complex(negInf, inf);
35      private Complex infNegInf = new Complex(inf, negInf);
36      private Complex infInf = new Complex(inf, inf);
37      private Complex negInfNegInf = new Complex(negInf, negInf);
38      private Complex infNaN = new Complex(inf, nan);
39  
40      public void testPolar2Complex() {
41          TestUtils.assertEquals(Complex.ONE, 
42                  ComplexUtils.polar2Complex(1, 0), 10e-12);
43          TestUtils.assertEquals(Complex.ZERO, 
44                  ComplexUtils.polar2Complex(0, 1), 10e-12);
45          TestUtils.assertEquals(Complex.ZERO, 
46                  ComplexUtils.polar2Complex(0, -1), 10e-12);
47          TestUtils.assertEquals(Complex.I, 
48                  ComplexUtils.polar2Complex(1, pi/2), 10e-12);
49          TestUtils.assertEquals(Complex.I.negate(), 
50                  ComplexUtils.polar2Complex(1, -pi/2), 10e-12);
51          double r = 0;
52          for (int i = 0; i < 5; i++) {
53            r += i;
54            double theta = 0;
55            for (int j =0; j < 20; j++) {
56                theta += pi / 6;
57                TestUtils.assertEquals(altPolar(r, theta), 
58                        ComplexUtils.polar2Complex(r, theta), 10e-12);
59            }
60            theta = -2 * pi;
61            for (int j =0; j < 20; j++) {
62                theta -= pi / 6;
63                TestUtils.assertEquals(altPolar(r, theta), 
64                        ComplexUtils.polar2Complex(r, theta), 10e-12);
65            }
66          }   
67      }
68  
69      protected Complex altPolar(double r, double theta) {
70          return Complex.I.multiply(new Complex(theta, 0)).exp().multiply(new Complex(r, 0));
71      }
72      
73      public void testPolar2ComplexIllegalModulus() {
74          try {
75              ComplexUtils.polar2Complex(-1, 0);
76              fail("Expecting IllegalArgumentException");
77          } catch (IllegalArgumentException ex) {
78              // expected
79          }       
80      }
81      
82      public void testPolar2ComplexNaN() {
83          TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(nan, 1));
84          TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(1, nan));
85          TestUtils.assertSame(Complex.NaN, 
86                  ComplexUtils.polar2Complex(nan, nan));     
87      }
88      
89      public void testPolar2ComplexInf() {
90          TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(1, inf));
91          TestUtils.assertSame(Complex.NaN,
92                  ComplexUtils.polar2Complex(1, negInf));
93          TestUtils.assertSame(Complex.NaN, ComplexUtils.polar2Complex(inf, inf));
94          TestUtils.assertSame(Complex.NaN,
95                  ComplexUtils.polar2Complex(inf, negInf));
96          TestUtils.assertSame(infInf, ComplexUtils.polar2Complex(inf, pi/4));
97          TestUtils.assertSame(infNaN, ComplexUtils.polar2Complex(inf, 0));
98          TestUtils.assertSame(infNegInf, ComplexUtils.polar2Complex(inf, -pi/4));
99          TestUtils.assertSame(negInfInf, ComplexUtils.polar2Complex(inf, 3*pi/4));
100         TestUtils.assertSame(negInfNegInf, ComplexUtils.polar2Complex(inf, 5*pi/4));
101     }
102 
103 }