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 large-state 64-bit generator suitable for {@code double} generation. This is slightly faster
22 * than the all-purpose generator {@link XoRoShiRo1024PlusPlus}.
23 *
24 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 1024 bits
25 * and the period is 2<sup>1024</sup>-1.</p>
26 *
27 * @see <a href="http://xorshift.di.unimi.it/xoroshiro1024star.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 XoRoShiRo1024Star extends AbstractXoRoShiRo1024 {
32 /**
33 * Creates a new instance.
34 *
35 * @param seed Initial seed.
36 * If the length is larger than 16, only the first 16 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 XoRoShiRo1024Star(long[] seed) {
41 super(seed);
42 }
43
44 /**
45 * Creates a copy instance.
46 *
47 * @param source Source to copy.
48 */
49 protected XoRoShiRo1024Star(XoRoShiRo1024Star source) {
50 super(source);
51 }
52
53 /** {@inheritDoc} */
54 @Override
55 protected long transform(long s0, long s15) {
56 return s0 * 0x9e3779b97f4a7c13L;
57 }
58
59 /** {@inheritDoc} */
60 @Override
61 protected XoRoShiRo1024Star copy() {
62 // This exists to ensure the jump function returns
63 // the correct class type. It should not be public.
64 return new XoRoShiRo1024Star(this);
65 }
66 }