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 generator.
22 *
23 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 512 bits
24 * and the period is 2<sup>512</sup>-1. Speed is expected to be slower than
25 * {@link XoShiRo256StarStar}.</p>
26 *
27 * @see <a href="http://xoshiro.di.unimi.it/xoshiro512starstar.c">Original source code</a>
28 * @see <a href="http://xoshiro.di.unimi.it/">xorshiro / xoroshiro generators</a>
29 * @since 1.3
30 */
31 public class XoShiRo512StarStar extends AbstractXoShiRo512 {
32 /**
33 * Creates a new instance.
34 *
35 * @param seed Initial seed.
36 * If the length is larger than 8, only the first 8 elements will
37 * be used; if smaller, the remaining elements will be automatically
38 * set. A seed containing all zeros will create a non-functional generator.
39 */
40 public XoShiRo512StarStar(long[] seed) {
41 super(seed);
42 }
43
44 /**
45 * Creates a new instance using an 8 element seed.
46 * A seed containing all zeros will create a non-functional generator.
47 *
48 * @param seed0 Initial seed element 0.
49 * @param seed1 Initial seed element 1.
50 * @param seed2 Initial seed element 2.
51 * @param seed3 Initial seed element 3.
52 * @param seed4 Initial seed element 4.
53 * @param seed5 Initial seed element 5.
54 * @param seed6 Initial seed element 6.
55 * @param seed7 Initial seed element 7.
56 */
57 public XoShiRo512StarStar(long seed0, long seed1, long seed2, long seed3,
58 long seed4, long seed5, long seed6, long seed7) {
59 super(seed0, seed1, seed2, seed3, seed4, seed5, seed6, seed7);
60 }
61
62 /**
63 * Creates a copy instance.
64 *
65 * @param source Source to copy.
66 */
67 protected XoShiRo512StarStar(XoShiRo512StarStar source) {
68 super(source);
69 }
70
71 /** {@inheritDoc} */
72 @Override
73 protected long nextOutput() {
74 return Long.rotateLeft(state1 * 5, 7) * 9;
75 }
76
77 /** {@inheritDoc} */
78 @Override
79 protected XoShiRo512StarStar copy() {
80 // This exists to ensure the jump function performed in the super class returns
81 // the correct class type. It should not be public.
82 return new XoShiRo512StarStar(this);
83 }
84 }