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.math4.legacy.analysis.integration.gauss;
18
19 import org.apache.commons.math4.legacy.analysis.UnivariateFunction;
20 import org.apache.commons.numbers.gamma.Gamma;
21 import org.apache.commons.math4.core.jdkmath.JdkMath;
22 import org.junit.Assert;
23 import org.junit.Test;
24
25 /**
26 * Test of the {@link LaguerreRuleFactory}.
27 */
28 public class LaguerreTest {
29 private static final GaussIntegratorFactory factory = new GaussIntegratorFactory();
30
31 @Test
32 public void testGamma() {
33 final double tol = 1e-13;
34
35 for (int i = 2; i < 10; i += 1) {
36 final double t = i;
37
38 final UnivariateFunction f = new UnivariateFunction() {
39 @Override
40 public double value(double x) {
41 return JdkMath.pow(x, t - 1);
42 }
43 };
44
45 final GaussIntegrator integrator = factory.laguerre(7);
46 final double s = integrator.integrate(f);
47 Assert.assertEquals(1d, Gamma.value(t) / s, tol);
48 }
49 }
50 }