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.rng.core.source32; 18 19 /** 20 * This class implements the WELL44497b pseudo-random number generator 21 * from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto. 22 * <p> 23 * This generator is described in a paper by François Panneton, 24 * Pierre L'Ecuyer and Makoto Matsumoto 25 * <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf"> 26 * Improved Long-Period Generators Based on Linear Recurrences Modulo 2</a> 27 * ACM Transactions on Mathematical Software, 32, 1 (2006). 28 * The errata for the paper are in 29 * <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng-errata.txt">wellrng-errata.txt</a>. 30 * </p> 31 * 32 * @see <a href="http://www.iro.umontreal.ca/~panneton/WELLRNG.html">WELL Random number generator</a> 33 * @since 1.0 34 */ 35 public class Well44497b extends Well44497a { 36 /** 37 * Creates a new random number generator. 38 * 39 * @param seed Initial seed. 40 */ 41 public Well44497b(int[] seed) { 42 super(seed); 43 } 44 45 /** {@inheritDoc} */ 46 @Override 47 public int next() { 48 int z4 = super.next(); 49 50 // Matsumoto-Kurita tempering to get a maximally equidistributed generator. 51 z4 ^= (z4 << 7) & 0x93dd1400; 52 z4 ^= (z4 << 15) & 0xfa118000; 53 54 return z4; 55 } 56 }