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.jupiter.api.Test;
28
29 import static org.junit.jupiter.api.Assertions.assertEquals;
30
31 /**
32 * Test of the {@link LaguerreRuleFactory}.
33 */
34 class LaguerreTest {
35 private static final GaussIntegratorFactory factory = new GaussIntegratorFactory();
36
37 @Test
38 void testGamma() {
39 final double tol = 1e-13;
40
41 for (int i = 2; i < 10; i += 1) {
42 final double t = i;
43
44 final UnivariateFunction f = new UnivariateFunction() {
45 @Override
46 public double value(double x) {
47 return FastMath.pow(x, t - 1);
48 }
49 };
50
51 final GaussIntegrator integrator = factory.laguerre(7);
52 final double s = integrator.integrate(f);
53 assertEquals(1d, Gamma.gamma(t) / s, tol);
54 }
55 }
56 }