XoShiRo512StarStar.java

  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. package org.apache.commons.rng.core.source64;

  18. /**
  19.  * A fast all-purpose generator.
  20.  *
  21.  * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 512 bits
  22.  * and the period is 2<sup>512</sup>-1. Speed is expected to be slower than
  23.  * {@link XoShiRo256StarStar}.</p>
  24.  *
  25.  * @see <a href="http://xoshiro.di.unimi.it/xoshiro512starstar.c">Original source code</a>
  26.  * @see <a href="http://xoshiro.di.unimi.it/">xorshiro / xoroshiro generators</a>
  27.  * @since 1.3
  28.  */
  29. public class XoShiRo512StarStar extends AbstractXoShiRo512 {
  30.     /**
  31.      * Creates a new instance.
  32.      *
  33.      * @param seed Initial seed.
  34.      * If the length is larger than 8, only the first 8 elements will
  35.      * be used; if smaller, the remaining elements will be automatically
  36.      * set. A seed containing all zeros will create a non-functional generator.
  37.      */
  38.     public XoShiRo512StarStar(long[] seed) {
  39.         super(seed);
  40.     }

  41.     /**
  42.      * Creates a new instance using an 8 element seed.
  43.      * A seed containing all zeros will create a non-functional generator.
  44.      *
  45.      * @param seed0 Initial seed element 0.
  46.      * @param seed1 Initial seed element 1.
  47.      * @param seed2 Initial seed element 2.
  48.      * @param seed3 Initial seed element 3.
  49.      * @param seed4 Initial seed element 4.
  50.      * @param seed5 Initial seed element 5.
  51.      * @param seed6 Initial seed element 6.
  52.      * @param seed7 Initial seed element 7.
  53.      */
  54.     public XoShiRo512StarStar(long seed0, long seed1, long seed2, long seed3,
  55.                               long seed4, long seed5, long seed6, long seed7) {
  56.         super(seed0, seed1, seed2, seed3, seed4, seed5, seed6, seed7);
  57.     }

  58.     /**
  59.      * Creates a copy instance.
  60.      *
  61.      * @param source Source to copy.
  62.      */
  63.     protected XoShiRo512StarStar(XoShiRo512StarStar source) {
  64.         super(source);
  65.     }

  66.     /** {@inheritDoc} */
  67.     @Override
  68.     protected long nextOutput() {
  69.         return Long.rotateLeft(state1 * 5, 7) * 9;
  70.     }

  71.     /** {@inheritDoc} */
  72.     @Override
  73.     protected XoShiRo512StarStar 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 XoShiRo512StarStar(this);
  77.     }
  78. }