1   //Licensed to the Apache Software Foundation (ASF) under one
2   //or more contributor license agreements.  See the NOTICE file
3   //distributed with this work for additional information
4   //regarding copyright ownership.  The ASF licenses this file
5   //to you under the Apache License, Version 2.0 (the
6   //"License"); you may not use this file except in compliance
7   //with 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,
12  //software distributed under the License is distributed on an
13  //"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14  //KIND, either express or implied.  See the License for the
15  //specific language governing permissions and limitations
16  //under the License.
17  
18  package org.apache.commons.math.random;
19  
20  import org.apache.commons.math.stat.StatUtils;
21  
22  import junit.framework.*;
23  
24  public class UniformRandomGeneratorTest
25  extends TestCase {
26  
27      public UniformRandomGeneratorTest(String name) {
28          super(name);
29      }
30  
31      public void testMeanAndStandardDeviation() {
32          RandomGenerator rg = new JDKRandomGenerator();
33          rg.setSeed(17399225432l);
34          UniformRandomGenerator generator = new UniformRandomGenerator(rg);
35          double[] sample = new double[10000];
36          for (int i = 0; i < sample.length; ++i) {
37              sample[i] = generator.nextNormalizedDouble();
38          }
39          assertEquals(0.0, StatUtils.mean(sample), 0.07);
40          assertEquals(1.0, StatUtils.variance(sample), 0.02);
41      }
42  
43      public static Test suite() {
44          return new TestSuite(UniformRandomGeneratorTest.class);
45      }
46  
47  }