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.numbers.field;
18
19 import java.util.List;
20 import java.util.function.BiPredicate;
21 import java.util.stream.Stream;
22 import java.util.ArrayList;
23
24 import org.apache.commons.numbers.fraction.Fraction;
25 import org.apache.commons.numbers.core.DD;
26 import org.apache.commons.numbers.core.Precision;
27 import org.apache.commons.numbers.fraction.BigFraction;
28
29 import org.junit.jupiter.api.Assertions;
30
31 /**
32 * List of fields.
33 */
34 final class FieldsList {
35 /** List of all fields implemented in the library. */
36 private static final List<FieldTestData<?>> LIST =
37 new ArrayList<>();
38
39 static {
40 try {
41 // List of fields to test.
42 add(FractionField.get(),
43 Fraction.of(13, 4),
44 Fraction.of(5, 29),
45 Fraction.of(-279, 11));
46 add(BigFractionField.get(),
47 BigFraction.of(13256093L, 43951044L),
48 BigFraction.of(543016315L, 29L),
49 BigFraction.of(-27930919051L, 11L));
50 add(FP64Field.get(),
51 FP64.of(23.45678901),
52 FP64.of(-543.2109876),
53 FP64.of(-234.5678901),
54 // double operations are subject to rounding so allow a tolerance
55 (x, y) -> Precision.equals(x.doubleValue(), y.doubleValue(), 1));
56 add(DDField.get(),
57 createDD(23.45678901, 4.5671892973),
58 createDD(-543.2109876, 5.237848286),
59 createDD(-234.5678901, -4.561268179),
60 // double-double operations are subject to rounding so allow a tolerance.
61 FieldsList::areEqual);
62 // Pass through a second DD that uses a signed negative zero
63 add(DDField.get(),
64 createDD(2.45678901, 45.671892973),
65 createDD(-54.32109876, 52.37848286),
66 createDD(-0.0, -0.0),
67 // double-double operations are subject to rounding so allow a tolerance.
68 FieldsList::areEqual);
69 } catch (Exception e) {
70 e.printStackTrace(System.err);
71 throw new RuntimeException(e);
72 }
73 }
74
75 private FieldsList() {}
76
77 /**
78 * @param field Field.
79 * @param a Field element.
80 * @param b Field element.
81 * @param c Field element.
82 */
83 private static <T> void add(Field<T> field,
84 T a,
85 T b,
86 T c) {
87 LIST.add(new FieldTestData<>(field, a, b, c));
88 }
89
90 /**
91 * @param field Field.
92 * @param a Field element.
93 * @param b Field element.
94 * @param c Field element.
95 * @param equals Field equality predicate.
96 */
97 private static <T> void add(Field<T> field,
98 T a,
99 T b,
100 T c,
101 BiPredicate<T, T> equals) {
102 LIST.add(new FieldTestData<>(field, a, b, c, equals));
103 }
104
105 /**
106 * Creates the double-double number from two random values.
107 * The second value is scaled so that it does not overlap the first.
108 *
109 * @param a Value.
110 * @param b Value.
111 * @return the number
112 */
113 private static DD createDD(double a, double b) {
114 final int ea = Math.getExponent(a);
115 final int eb = Math.getExponent(b);
116 // Scale to have a non-overlapping 53-bit mantissa
117 double bb = Math.scalb(b, ea - eb - 53);
118 // If b has a larger mantissa than a (ignoring the exponent) then an overlap may occur
119 if (a != a + bb) {
120 bb *= 0.5;
121 }
122 Assertions.assertEquals(a, a + bb);
123 return DD.ofSum(a, bb);
124 }
125
126 /**
127 * Test if the two numbers are equal.
128 *
129 * @param x Value.
130 * @param y Value.
131 * @return true if equal
132 */
133 private static boolean areEqual(DD x, DD y) {
134 // A simple binary equality is fine for most cases.
135 if (x.equals(y)) {
136 return true;
137 }
138 // If the high part is the same we can test a ULP tolerance on the low part.
139 if (x.hi() == y.hi() && Precision.equals(x.lo(), y.lo(), 1)) {
140 return true;
141 }
142 // Note that the high part could be different by 1 ulp and then the low part
143 // can be significantly different (opposite signed values) to create numbers that
144 // are almost the same: x+xx ~ y-yy.
145 // Here we obtain the difference and use a relative error of 2^-105:
146 // | x - y |
147 // ------------ <= relative error
148 // max(|x|, |y|)
149 return Math.abs(x.subtract(y).doubleValue()) /
150 Math.max(Math.abs(x.doubleValue()), Math.abs(y.doubleValue())) <= Math.pow(2, -105);
151 }
152
153 /**
154 * Subclasses that are "parametric" tests can forward the call to
155 * the "@Parameters"-annotated method to this method.
156 *
157 * @return the stream of all fields.
158 */
159 static Stream<FieldTestData<?>> stream() {
160 return LIST.stream();
161 }
162 }