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 * A Permuted Congruential Generator (PCG) that is composed of a 64-bit Multiplicative Congruential 021 * Generator (MCG) combined with the XSH-RR (xorshift; random rotate) output 022 * transformation to create 32-bit output. 023 * 024 * <p>State size is 64 bits and the period is 2<sup>62</sup>.</p> 025 * 026 * @see <a href="http://www.pcg-random.org/"> 027 * PCG, A Family of Better Random Number Generators</a> 028 * @since 1.3 029 */ 030public class PcgMcgXshRr32 extends AbstractPcgMcg6432 { 031 /** 032 * Creates a new instance. 033 * 034 * @param seed Initial seed. 035 */ 036 public PcgMcgXshRr32(Long seed) { 037 super(seed); 038 } 039 040 /** {@inheritDoc} */ 041 @Override 042 protected int transform(long x) { 043 final int count = (int)(x >>> 59); 044 return Integer.rotateRight((int)((x ^ (x >>> 18)) >>> 27), count); 045 } 046}