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Diffstat (limited to 'src/main/java/org/apache/commons/math/random/UniformRandomGenerator.java')
-rw-r--r-- | src/main/java/org/apache/commons/math/random/UniformRandomGenerator.java | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/random/UniformRandomGenerator.java b/src/main/java/org/apache/commons/math/random/UniformRandomGenerator.java new file mode 100644 index 0000000..54492d0 --- /dev/null +++ b/src/main/java/org/apache/commons/math/random/UniformRandomGenerator.java @@ -0,0 +1,61 @@ +/* + * 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.math.random; + +import org.apache.commons.math.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 + * + * @version $Revision: 990655 $ $Date: 2010-08-29 23:49:40 +0200 (dim. 29 août 2010) $ + */ + +public class UniformRandomGenerator implements NormalizedRandomGenerator { + + /** Serializable version identifier. */ + private static final long serialVersionUID = 1569292426375546027L; + + /** 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); + } + +} |