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 * https://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 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.util;
23
24 import org.hipparchus.exception.MathIllegalStateException;
25 import org.junit.jupiter.api.Test;
26
27 import static org.junit.jupiter.api.Assertions.assertEquals;
28 import static org.junit.jupiter.api.Assertions.assertThrows;
29
30 /**
31 * Tests for ContinuedFraction.
32 */
33 class ContinuedFractionTest {
34
35 @Test
36 void testGoldenRatio() throws Exception {
37 ContinuedFraction cf = new ContinuedFraction() {
38
39 @Override
40 public double getA(int n, double x) {
41 return 1.0;
42 }
43
44 @Override
45 public double getB(int n, double x) {
46 return 1.0;
47 }
48 };
49
50 double gr = cf.evaluate(0.0, 10e-9);
51 assertEquals(1.61803399, gr, 10e-9);
52 }
53
54 @Test
55 void testNonConvergentContinuedFraction() {
56 assertThrows(MathIllegalStateException.class, () -> {
57 ContinuedFraction cf = new ContinuedFraction() {
58
59 @Override
60 public double getA(int n, double x) {
61 return 1.0;
62 }
63
64 @Override
65 public double getB(int n, double x) {
66 return 1.0;
67 }
68
69 };
70
71 cf.evaluate(0.0, 10e-9, 10);
72 });
73 }
74
75 @Test
76 void testInfinityDivergence() {
77 assertThrows(MathIllegalStateException.class, () -> {
78 ContinuedFraction cf = new ContinuedFraction() {
79
80 @Override
81 public double getA(int n, double x) {
82 return 1. / n;
83 }
84
85 @Override
86 public double getB(int n, double x) {
87 return 1.0;
88 }
89
90 };
91
92 cf.evaluate(1);
93 });
94 }
95 }