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1 | /////////////////////////////////////////////////////////////////////////// |
2 | // | |
3 | // Copyright 2010 | |
4 | // | |
5 | // This file is part of starlight. | |
6 | // | |
7 | // starlight is free software: you can redistribute it and/or modify | |
8 | // it under the terms of the GNU General Public License as published by | |
9 | // the Free Software Foundation, either version 3 of the License, or | |
10 | // (at your option) any later version. | |
11 | // | |
12 | // starlight is distributed in the hope that it will be useful, | |
13 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | // GNU General Public License for more details. | |
16 | // | |
17 | // You should have received a copy of the GNU General Public License | |
18 | // along with starlight. If not, see <http://www.gnu.org/licenses/>. | |
19 | // | |
20 | /////////////////////////////////////////////////////////////////////////// | |
21 | // | |
22 | // File and Version Information: | |
23 | // $Rev:: $: revision of last commit | |
24 | // $Author:: $: author of last commit | |
25 | // $Date:: $: date of last commit | |
26 | // | |
27 | // Description: | |
28 | // | |
29 | // | |
30 | // | |
31 | /////////////////////////////////////////////////////////////////////////// | |
32 | ||
33 | ||
34 | #include <iostream> | |
35 | #include <fstream> | |
36 | #include <cmath> | |
37 | ||
38 | #include "randomgenerator.h" | |
39 | ||
40 | ||
41 | using namespace std; | |
42 | ||
43 | ||
44 | //USED IN ROOT under TRANDOM3 | |
45 | // Random number generator class based on | |
46 | // M. Matsumoto and T. Nishimura, | |
47 | // Mersenne Twistor: A 623-diminsionally equidistributed | |
48 | // uniform pseudorandom number generator | |
49 | // ACM Transactions on Modeling and Computer Simulation, | |
50 | // Vol. 8, No. 1, January 1998, pp 3--30. | |
51 | // | |
52 | // For more information see the Mersenne Twistor homepage | |
53 | // http://www.math.keio.ac.jp/~matumoto/emt.html | |
54 | // | |
55 | // Advantage: large period 2**19937-1 | |
56 | // relativly fast | |
57 | // (only two times slower than TRandom, but | |
58 | // two times faster than TRandom2) | |
59 | // Drawback: a relative large internal state of 624 integers | |
60 | // | |
61 | // | |
62 | // Aug.99 ROOT implementation based on CLHEP by P.Malzacher | |
63 | // | |
64 | // the original code contains the following copyright notice: | |
65 | /* This library is free software; you can redistribute it and/or */ | |
66 | /* modify it under the terms of the GNU Library General Public */ | |
67 | /* License as published by the Free Software Foundation; either */ | |
68 | /* version 2 of the License, or (at your option) any later */ | |
69 | /* version. */ | |
70 | /* This library is distributed in the hope that it will be useful, */ | |
71 | /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ | |
72 | /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. */ | |
73 | /* See the GNU Library General Public License for more details. */ | |
74 | /* You should have received a copy of the GNU Library General */ | |
75 | /* Public License along with this library; if not, write to the */ | |
76 | /* Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA */ | |
77 | /* 02111-1307 USA */ | |
78 | /* Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura. */ | |
79 | /* When you use this, send an email to: matumoto@math.keio.ac.jp */ | |
80 | /* with an appropriate reference to your work. */ | |
81 | ///////////////////////////////////////////////////////////////////// | |
82 | ||
83 | ||
84 | void randomGenerator::SetSeed(unsigned int seed) | |
85 | { | |
86 | // Set the random generator sequence | |
87 | // if seed is 0 (default value) a TUUID is generated and used to fill | |
88 | // the first 8 integers of the seed array. | |
89 | // In this case the seed is guaranteed to be unique in space and time. | |
90 | // Use upgraded seeding procedure to fix a known problem when seeding with values | |
91 | // with many zero in the bit pattern (like 2**28). | |
92 | // see http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html | |
93 | ||
94 | Lockguard<MutexPosix> guard(&_mutex); | |
95 | ||
96 | _count624 = 624; | |
97 | int i,j; | |
98 | ||
99 | _Mt[0] = seed; | |
100 | j = 1; | |
101 | // use multipliers from Knuth's "Art of Computer Programming" Vol. 2, 3rd Ed. p.106 | |
102 | for(i=j; i<624; i++) { | |
103 | _Mt[i] = (1812433253 * ( _Mt[i-1] ^ ( _Mt[i-1] >> 30)) + i); | |
104 | } | |
105 | } | |
106 | ||
107 | ||
108 | double randomGenerator::Rndom(int) | |
109 | { | |
110 | ||
111 | // Machine independent random number generator. | |
112 | // Produces uniformly-distributed floating points in ]0,1] | |
113 | // Method: Mersenne Twistor | |
114 | ||
115 | Lockguard<MutexPosix> guard(&_mutex); | |
116 | ||
117 | unsigned int y; | |
118 | ||
119 | const int kM = 397; | |
120 | const int kN = 624; | |
121 | const unsigned int kTemperingMaskB = 0x9d2c5680; | |
122 | const unsigned int kTemperingMaskC = 0xefc60000; | |
123 | const unsigned int kUpperMask = 0x80000000; | |
124 | const unsigned int kLowerMask = 0x7fffffff; | |
125 | const unsigned int kMatrixA = 0x9908b0df; | |
126 | ||
127 | if (_count624 >= kN) { | |
128 | register int i; | |
129 | ||
130 | for (i=0; i < kN-kM; i++) { | |
131 | y = (_Mt[i] & kUpperMask) | (_Mt[i+1] & kLowerMask); | |
132 | _Mt[i] = _Mt[i+kM] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0); | |
133 | } | |
134 | ||
135 | for ( ; i < kN-1 ; i++) { | |
136 | y = (_Mt[i] & kUpperMask) | (_Mt[i+1] & kLowerMask); | |
137 | _Mt[i] = _Mt[i+kM-kN] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0); | |
138 | } | |
139 | ||
140 | y = (_Mt[kN-1] & kUpperMask) | (_Mt[0] & kLowerMask); | |
141 | _Mt[kN-1] = _Mt[kM-1] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0); | |
142 | _count624 = 0; | |
143 | } | |
144 | ||
145 | y = _Mt[_count624++]; | |
146 | y ^= (y >> 11); | |
147 | y ^= ((y << 7 ) & kTemperingMaskB ); | |
148 | y ^= ((y << 15) & kTemperingMaskC ); | |
149 | y ^= (y >> 18); | |
150 | ||
151 | if (y) return ( (double) y * 2.3283064365386963e-10); // * Power(2,-32) | |
152 | return Rndom(); | |
153 | } |