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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  package org.apache.commons.geometry.euclidean.internal;
18  
19  import org.apache.commons.geometry.core.GeometryTestUtils;
20  import org.junit.jupiter.api.Assertions;
21  import org.junit.jupiter.api.Test;
22  
23  class MatricesTest {
24  
25      private static final double EPS = 1e-12;
26  
27      @Test
28      void testDeterminant_2x2() {
29          // act/assert
30          Assertions.assertEquals(1, Matrices.determinant(
31                  1, 0,
32                  0, 1), EPS);
33  
34          Assertions.assertEquals(-1, Matrices.determinant(
35                  -1, 0,
36                  0, 1), EPS);
37  
38          Assertions.assertEquals(0, Matrices.determinant(
39                  1, 1,
40                  1, 1), EPS);
41  
42          Assertions.assertEquals(-2, Matrices.determinant(
43                  1, 2,
44                  3, 4), EPS);
45  
46          Assertions.assertEquals(7, Matrices.determinant(
47                  -5, -4,
48                  -2, -3), EPS);
49  
50          Assertions.assertEquals(9, Matrices.determinant(
51                  -1, -2,
52                  6, 3), EPS);
53      }
54  
55      @Test
56      void testDeterminant_3x3() {
57          // act/assert
58          Assertions.assertEquals(1, Matrices.determinant(
59                  1, 0, 0,
60                  0, 1, 0,
61                  0, 0, 1), EPS);
62  
63          Assertions.assertEquals(-1, Matrices.determinant(
64                  -1, 0, 0,
65                  0, -1, 0,
66                  0, 0, -1), EPS);
67  
68          Assertions.assertEquals(0, Matrices.determinant(
69                  1, 2, 3,
70                  4, 5, 6,
71                  7, 8, 9), EPS);
72  
73          Assertions.assertEquals(49, Matrices.determinant(
74                  2, -3, 1,
75                  2, 0, -1,
76                  1, 4, 5), EPS);
77  
78          Assertions.assertEquals(-40, Matrices.determinant(
79                  -5, 0, -1,
80                  1, 2, -1,
81                  -3, 4, 1
82                  ), EPS);
83      }
84  
85      @Test
86      void testCheckDeterminantForInverse() {
87          // act/assert
88          Assertions.assertEquals(1.0, Matrices.checkDeterminantForInverse(1.0), EPS);
89          Assertions.assertEquals(-1.0, Matrices.checkDeterminantForInverse(-1.0), EPS);
90      }
91  
92      @Test
93      void testCheckDeterminantForInverse_invalid() {
94          // act/assert
95          GeometryTestUtils.assertThrowsWithMessage(() -> {
96              Matrices.checkDeterminantForInverse(0);
97          }, IllegalStateException.class, "Matrix is not invertible; matrix determinant is 0.0");
98  
99          GeometryTestUtils.assertThrowsWithMessage(() -> {
100             Matrices.checkDeterminantForInverse(Double.NaN);
101         }, IllegalStateException.class, "Matrix is not invertible; matrix determinant is NaN");
102 
103         GeometryTestUtils.assertThrowsWithMessage(() -> {
104             Matrices.checkDeterminantForInverse(Double.POSITIVE_INFINITY);
105         }, IllegalStateException.class, "Matrix is not invertible; matrix determinant is Infinity");
106 
107         GeometryTestUtils.assertThrowsWithMessage(() -> {
108             Matrices.checkDeterminantForInverse(Double.NEGATIVE_INFINITY);
109         }, IllegalStateException.class, "Matrix is not invertible; matrix determinant is -Infinity");
110     }
111 
112     @Test
113     void testCheckElementForInverse() {
114         // act/assert
115         Assertions.assertEquals(0.0, Matrices.checkElementForInverse(0.0), EPS);
116 
117         Assertions.assertEquals(1.0, Matrices.checkElementForInverse(1.0), EPS);
118         Assertions.assertEquals(-1.0, Matrices.checkElementForInverse(-1.0), EPS);
119     }
120 
121     @Test
122     void testCheckElementForInverse_invalid() {
123         // act/assert
124         GeometryTestUtils.assertThrowsWithMessage(() -> {
125             Matrices.checkElementForInverse(Double.NaN);
126         }, IllegalStateException.class, "Matrix is not invertible; invalid matrix element: NaN");
127 
128         GeometryTestUtils.assertThrowsWithMessage(() -> {
129             Matrices.checkElementForInverse(Double.POSITIVE_INFINITY);
130         }, IllegalStateException.class, "Matrix is not invertible; invalid matrix element: Infinity");
131 
132         GeometryTestUtils.assertThrowsWithMessage(() -> {
133             Matrices.checkElementForInverse(Double.NEGATIVE_INFINITY);
134         }, IllegalStateException.class, "Matrix is not invertible; invalid matrix element: -Infinity");
135     }
136 }