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 all-purpose 64-bit generator.
22 *
23 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 1024 bits
24 * and the period is 2<sup>1024</sup>-1.</p>
25 *
26 * <p>Note: This can be used as a replacement for {@link XorShift1024Star}.</p>
27 *
28 * @see <a href="http://xorshift.di.unimi.it/xoroshiro1024starstar.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 XoRoShiRo1024StarStar extends AbstractXoRoShiRo1024 {
33 /**
34 * Creates a new instance.
35 *
36 * @param seed Initial seed.
37 * If the length is larger than 16, only the first 16 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 XoRoShiRo1024StarStar(long[] seed) {
42 super(seed);
43 }
44
45 /**
46 * Creates a copy instance.
47 *
48 * @param source Source to copy.
49 */
50 protected XoRoShiRo1024StarStar(XoRoShiRo1024StarStar source) {
51 super(source);
52 }
53
54 /** {@inheritDoc} */
55 @Override
56 protected long transform(long s0, long s15) {
57 return Long.rotateLeft(s0 * 5, 7) * 9;
58 }
59
60 /** {@inheritDoc} */
61 @Override
62 protected XoRoShiRo1024StarStar copy() {
63 // This exists to ensure the jump function returns
64 // the correct class type. It should not be public.
65 return new XoRoShiRo1024StarStar(this);
66 }
67 }