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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    *      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.analysis.integration.gauss;
23  
24  import org.hipparchus.exception.LocalizedCoreFormats;
25  import org.hipparchus.exception.MathIllegalArgumentException;
26  import org.hipparchus.util.Binary64;
27  import org.hipparchus.util.Binary64Field;
28  import org.hipparchus.util.FastMath;
29  import org.junit.Assert;
30  import org.junit.Test;
31  
32  /**
33   * Test of the {@link FieldLegendreRuleFactory}.
34   *
35   */
36  public class FieldLegendreTest {
37      private static final FieldGaussIntegratorFactory<Binary64> factory = new FieldGaussIntegratorFactory<>(Binary64Field.getInstance());
38  
39      @Test
40      public void testTooLArgeNumberOfPoints() {
41          try {
42              factory.legendre(10000, new Binary64(0), new Binary64(Math.PI / 2));
43              Assert.fail("an exception should have been thrown");
44          } catch (MathIllegalArgumentException miae) {
45              Assert.assertEquals(LocalizedCoreFormats.NUMBER_TOO_LARGE, miae.getSpecifier());
46              Assert.assertEquals(10000, ((Integer) miae.getParts()[0]).intValue());
47              Assert.assertEquals(1000,  ((Integer) miae.getParts()[1]).intValue());
48          }
49      }
50  
51      @Test
52      public void testCos() {
53          final FieldGaussIntegrator<Binary64> integrator = factory.legendre(7, new Binary64(0), new Binary64(Math.PI / 2));
54          final double s = integrator.integrate(x -> FastMath.cos(x)).getReal();
55          // System.out.println("s=" + s + " e=" + 1);
56          Assert.assertEquals(1, s, Math.ulp(1d));
57      }
58  
59  
60      @Test
61      public void testInverse() {
62  
63          final Binary64 lo = new Binary64(12.34);
64          final Binary64 hi = new Binary64(456.78);
65  
66          final FieldGaussIntegrator<Binary64> integrator = factory.legendre(60, lo, hi);
67          final double s = integrator.integrate(x -> x.reciprocal()).getReal();
68          final double expected = FastMath.log(hi).subtract(FastMath.log(lo)).getReal();
69          // System.out.println("s=" + s + " e=" + expected);
70          Assert.assertEquals(expected, s, 1e-14);
71      }
72  }