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.analysis.UnivariateFunction;
25 import org.hipparchus.special.Gamma;
26 import org.hipparchus.util.FastMath;
27 import org.junit.Assert;
28 import org.junit.Test;
29
30 /**
31 * Test of the {@link LaguerreRuleFactory}.
32 */
33 public class LaguerreTest {
34 private static final GaussIntegratorFactory factory = new GaussIntegratorFactory();
35
36 @Test
37 public void testGamma() {
38 final double tol = 1e-13;
39
40 for (int i = 2; i < 10; i += 1) {
41 final double t = i;
42
43 final UnivariateFunction f = new UnivariateFunction() {
44 @Override
45 public double value(double x) {
46 return FastMath.pow(x, t - 1);
47 }
48 };
49
50 final GaussIntegrator integrator = factory.laguerre(7);
51 final double s = integrator.integrate(f);
52 Assert.assertEquals(1d, Gamma.gamma(t) / s, tol);
53 }
54 }
55 }