| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.commons.math3.random; |
| |
| import org.apache.commons.math3.util.FastMath; |
| |
| /** |
| * This class implements a normalized uniform random generator. |
| * <p>Since it is a normalized random generator, it generates values |
| * from a uniform distribution with mean equal to 0 and standard |
| * deviation equal to 1. Generated values fall in the range |
| * [-√3, +√3].</p> |
| * |
| * @since 1.2 |
| * |
| */ |
| |
| public class UniformRandomGenerator implements NormalizedRandomGenerator { |
| |
| /** Square root of three. */ |
| private static final double SQRT3 = FastMath.sqrt(3.0); |
| |
| /** Underlying generator. */ |
| private final RandomGenerator generator; |
| |
| /** Create a new generator. |
| * @param generator underlying random generator to use |
| */ |
| public UniformRandomGenerator(RandomGenerator generator) { |
| this.generator = generator; |
| } |
| |
| /** Generate a random scalar with null mean and unit standard deviation. |
| * <p>The number generated is uniformly distributed between -&sqrt;(3) |
| * and +&sqrt;(3).</p> |
| * @return a random scalar with null mean and unit standard deviation |
| */ |
| public double nextNormalizedDouble() { |
| return SQRT3 * (2 * generator.nextDouble() - 1.0); |
| } |
| |
| } |