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 RNG implementing the {@code XorShift1024*} algorithm. 22 * 23 * <p>Note: This supersedes {@link XorShift1024Star}. The sequences emitted by both 24 * generators are correlated.</p> 25 * 26 * <p>This generator differs only in the final multiplier (a fixed-point representation 27 * of the golden ratio), which eliminates linear dependencies from one of the lowest 28 * bits.</p> 29 * 30 * @see <a href="http://xorshift.di.unimi.it/xorshift1024star.c">Original source code</a> 31 * @see <a href="https://en.wikipedia.org/wiki/Xorshift">Xorshift (Wikipedia)</a> 32 * @since 1.3 33 */ 34 public class XorShift1024StarPhi extends XorShift1024Star { 35 /** 36 * Creates a new instance. 37 * 38 * @param seed Initial seed. 39 * If the length is larger than 16, only the first 16 elements will 40 * be used; if smaller, the remaining elements will be automatically 41 * set. A seed containing all zeros will create a non-functional generator. 42 */ 43 public XorShift1024StarPhi(long[] seed) { 44 super(seed, 0x9e3779b97f4a7c13L); 45 } 46 47 /** 48 * Creates a copy instance. 49 * 50 * @param source Source to copy. 51 */ 52 protected XorShift1024StarPhi(XorShift1024StarPhi source) { 53 super(source); 54 } 55 56 /** {@inheritDoc} */ 57 @Override 58 protected XorShift1024StarPhi copy() { 59 // This exists to ensure the jump function performed in the super class returns 60 // the correct class type. It should not be public. 61 return new XorShift1024StarPhi(this); 62 } 63 }