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 64-bit generator suitable for {@code double} generation. This is slightly faster than the 22 * all-purpose generator {@link XoShiRo512StarStar}. 23 * 24 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 512 bits 25 * and the period is 2<sup>512</sup>-1. Speed is expected to be slower than 26 * {@link XoShiRo256Plus}.</p> 27 * 28 * @see <a href="http://xoshiro.di.unimi.it/xoshiro512plus.c">Original source code</a> 29 * @see <a href="http://xoshiro.di.unimi.it/">xorshiro / xoroshiro generators</a> 30 * @since 1.3 31 */ 32 public class XoShiRo512Plus extends AbstractXoShiRo512 { 33 /** 34 * Creates a new instance. 35 * 36 * @param seed Initial seed. 37 * If the length is larger than 8, only the first 8 elements will 38 * be used; if smaller, the remaining elements will be automatically 39 * set. A seed containing all zeros will create a non-functional generator. 40 */ 41 public XoShiRo512Plus(long[] seed) { 42 super(seed); 43 } 44 45 /** 46 * Creates a new instance using an 8 element seed. 47 * A seed containing all zeros will create a non-functional generator. 48 * 49 * @param seed0 Initial seed element 0. 50 * @param seed1 Initial seed element 1. 51 * @param seed2 Initial seed element 2. 52 * @param seed3 Initial seed element 3. 53 * @param seed4 Initial seed element 4. 54 * @param seed5 Initial seed element 5. 55 * @param seed6 Initial seed element 6. 56 * @param seed7 Initial seed element 7. 57 */ 58 public XoShiRo512Plus(long seed0, long seed1, long seed2, long seed3, 59 long seed4, long seed5, long seed6, long seed7) { 60 super(seed0, seed1, seed2, seed3, seed4, seed5, seed6, seed7); 61 } 62 63 /** 64 * Creates a copy instance. 65 * 66 * @param source Source to copy. 67 */ 68 protected XoShiRo512Plus(XoShiRo512Plus source) { 69 super(source); 70 } 71 72 /** {@inheritDoc} */ 73 @Override 74 protected long nextOutput() { 75 return state0 + state2; 76 } 77 78 /** {@inheritDoc} */ 79 @Override 80 protected XoShiRo512Plus copy() { 81 // This exists to ensure the jump function performed in the super class returns 82 // the correct class type. It should not be public. 83 return new XoShiRo512Plus(this); 84 } 85 }