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Java example source code file (Well512a.java)

This example Java source code file (Well512a.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

abstractwell, override, well512a

The Well512a.java Java example source code

/*
 * 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;


/** This class implements the WELL512a pseudo-random number generator
 * from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto.

 * <p>This generator is described in a paper by François Panneton,
 * Pierre L'Ecuyer and Makoto Matsumoto <a
 * href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf">Improved
 * Long-Period Generators Based on Linear Recurrences Modulo 2</a> ACM
 * Transactions on Mathematical Software, 32, 1 (2006). The errata for the paper
 * are in <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng-errata.txt">wellrng-errata.txt.

* @see <a href="http://www.iro.umontreal.ca/~panneton/WELLRNG.html">WELL Random number generator * @since 2.2 */ public class Well512a extends AbstractWell { /** Serializable version identifier. */ private static final long serialVersionUID = -6104179812103820574L; /** Number of bits in the pool. */ private static final int K = 512; /** First parameter of the algorithm. */ private static final int M1 = 13; /** Second parameter of the algorithm. */ private static final int M2 = 9; /** Third parameter of the algorithm. */ private static final int M3 = 5; /** Creates a new random number generator. * <p>The instance is initialized using the current time as the * seed.</p> */ public Well512a() { super(K, M1, M2, M3); } /** Creates a new random number generator using a single int seed. * @param seed the initial seed (32 bits integer) */ public Well512a(int seed) { super(K, M1, M2, M3, seed); } /** Creates a new random number generator using an int array seed. * @param seed the initial seed (32 bits integers array), if null * the seed of the generator will be related to the current time */ public Well512a(int[] seed) { super(K, M1, M2, M3, seed); } /** Creates a new random number generator using a single long seed. * @param seed the initial seed (64 bits integer) */ public Well512a(long seed) { super(K, M1, M2, M3, seed); } /** {@inheritDoc} */ @Override protected int next(final int bits) { final int indexRm1 = iRm1[index]; final int vi = v[index]; final int vi1 = v[i1[index]]; final int vi2 = v[i2[index]]; final int z0 = v[indexRm1]; // the values below include the errata of the original article final int z1 = (vi ^ (vi << 16)) ^ (vi1 ^ (vi1 << 15)); final int z2 = vi2 ^ (vi2 >>> 11); final int z3 = z1 ^ z2; final int z4 = (z0 ^ (z0 << 2)) ^ (z1 ^ (z1 << 18)) ^ (z2 << 28) ^ (z3 ^ ((z3 << 5) & 0xda442d24)); v[index] = z3; v[indexRm1] = z4; index = indexRm1; return z4 >>> (32 - bits); } }

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