source: src/main/java/agents/anac/y2019/harddealer/math3/random/Well19937a.java

Last change on this file was 200, checked in by Katsuhide Fujita, 5 years ago

Add ANAC 2019 agents

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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 */
17package agents.anac.y2019.harddealer.math3.random;
18
19
20/** This class implements the WELL19937a pseudo-random number generator
21 * from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto.
22
23 * <p>This generator is described in a paper by Fran&ccedil;ois Panneton,
24 * Pierre L'Ecuyer and Makoto Matsumoto <a
25 * href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf">Improved
26 * Long-Period Generators Based on Linear Recurrences Modulo 2</a> ACM
27 * Transactions on Mathematical Software, 32, 1 (2006). The errata for the paper
28 * are in <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng-errata.txt">wellrng-errata.txt</a>.</p>
29
30 * @see <a href="http://www.iro.umontreal.ca/~panneton/WELLRNG.html">WELL Random number generator</a>
31 * @since 2.2
32
33 */
34public class Well19937a extends AbstractWell {
35
36 /** Serializable version identifier. */
37 private static final long serialVersionUID = -7462102162223815419L;
38
39 /** Number of bits in the pool. */
40 private static final int K = 19937;
41
42 /** First parameter of the algorithm. */
43 private static final int M1 = 70;
44
45 /** Second parameter of the algorithm. */
46 private static final int M2 = 179;
47
48 /** Third parameter of the algorithm. */
49 private static final int M3 = 449;
50
51 /** Creates a new random number generator.
52 * <p>The instance is initialized using the current time as the
53 * seed.</p>
54 */
55 public Well19937a() {
56 super(K, M1, M2, M3);
57 }
58
59 /** Creates a new random number generator using a single int seed.
60 * @param seed the initial seed (32 bits integer)
61 */
62 public Well19937a(int seed) {
63 super(K, M1, M2, M3, seed);
64 }
65
66 /** Creates a new random number generator using an int array seed.
67 * @param seed the initial seed (32 bits integers array), if null
68 * the seed of the generator will be related to the current time
69 */
70 public Well19937a(int[] seed) {
71 super(K, M1, M2, M3, seed);
72 }
73
74 /** Creates a new random number generator using a single long seed.
75 * @param seed the initial seed (64 bits integer)
76 */
77 public Well19937a(long seed) {
78 super(K, M1, M2, M3, seed);
79 }
80
81 /** {@inheritDoc} */
82 @Override
83 protected int next(final int bits) {
84
85 final int indexRm1 = iRm1[index];
86 final int indexRm2 = iRm2[index];
87
88 final int v0 = v[index];
89 final int vM1 = v[i1[index]];
90 final int vM2 = v[i2[index]];
91 final int vM3 = v[i3[index]];
92
93 final int z0 = (0x80000000 & v[indexRm1]) ^ (0x7FFFFFFF & v[indexRm2]);
94 final int z1 = (v0 ^ (v0 << 25)) ^ (vM1 ^ (vM1 >>> 27));
95 final int z2 = (vM2 >>> 9) ^ (vM3 ^ (vM3 >>> 1));
96 final int z3 = z1 ^ z2;
97 final int z4 = z0 ^ (z1 ^ (z1 << 9)) ^ (z2 ^ (z2 << 21)) ^ (z3 ^ (z3 >>> 21));
98
99 v[index] = z3;
100 v[indexRm1] = z4;
101 v[indexRm2] &= 0x80000000;
102 index = indexRm1;
103
104 return z4 >>> (32 - bits);
105
106 }
107}
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