001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.rng.core.source32; 018 019/** 020 * This class implements the WELL19937c pseudo-random number generator 021 * from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto. 022 * <p> 023 * This generator is described in a paper by François Panneton, 024 * Pierre L'Ecuyer and Makoto Matsumoto 025 * <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf"> 026 * Improved Long-Period Generators Based on Linear Recurrences Modulo 2</a> 027 * ACM Transactions on Mathematical Software, 32, 1 (2006). 028 * The errata for the paper are in 029 * <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng-errata.txt">wellrng-errata.txt</a>. 030 * </p> 031 * 032 * @see <a href="http://www.iro.umontreal.ca/~panneton/WELLRNG.html">WELL Random number generator</a> 033 * @since 1.0 034 */ 035public class Well19937c extends Well19937a { 036 /** 037 * Creates a new random number generator. 038 * 039 * @param seed Initial seed. 040 */ 041 public Well19937c(int[] seed) { 042 super(seed); 043 } 044 045 /** {@inheritDoc} */ 046 @Override 047 public int next() { 048 int z4 = super.next(); 049 050 // Matsumoto-Kurita tempering to get a maximally equidistributed generator. 051 z4 ^= (z4 << 7) & 0xe46e1700; 052 z4 ^= (z4 << 15) & 0x9b868000; 053 054 return z4; 055 } 056}