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 18 package org.apache.commons.rng.core.source64; 19 20 /** 21 * A fast all-purpose 64-bit generator. 22 * 23 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 256 bits 24 * and the period is 2<sup>256</sup>-1.</p> 25 * 26 * @see <a href="http://xoshiro.di.unimi.it/xoshiro256starstar.c">Original source code</a> 27 * @see <a href="http://xoshiro.di.unimi.it/">xorshiro / xoroshiro generators</a> 28 * @since 1.3 29 */ 30 public class XoShiRo256StarStar extends AbstractXoShiRo256 { 31 /** 32 * Creates a new instance. 33 * 34 * @param seed Initial seed. 35 * If the length is larger than 4, only the first 4 elements will 36 * be used; if smaller, the remaining elements will be automatically 37 * set. A seed containing all zeros will create a non-functional generator. 38 */ 39 public XoShiRo256StarStar(long[] seed) { 40 super(seed); 41 } 42 43 /** 44 * Creates a new instance using a 4 element seed. 45 * A seed containing all zeros will create a non-functional generator. 46 * 47 * @param seed0 Initial seed element 0. 48 * @param seed1 Initial seed element 1. 49 * @param seed2 Initial seed element 2. 50 * @param seed3 Initial seed element 3. 51 */ 52 public XoShiRo256StarStar(long seed0, long seed1, long seed2, long seed3) { 53 super(seed0, seed1, seed2, seed3); 54 } 55 56 /** 57 * Creates a copy instance. 58 * 59 * @param source Source to copy. 60 */ 61 protected XoShiRo256StarStar(XoShiRo256StarStar source) { 62 super(source); 63 } 64 65 /** {@inheritDoc} */ 66 @Override 67 protected long nextOutput() { 68 return Long.rotateLeft(state1 * 5, 7) * 9; 69 } 70 71 /** {@inheritDoc} */ 72 @Override 73 protected XoShiRo256StarStar copy() { 74 // This exists to ensure the jump function performed in the super class returns 75 // the correct class type. It should not be public. 76 return new XoShiRo256StarStar(this); 77 } 78 }