1 ///////////////////////////////////////////////////////////////////////////
5 // This file is part of starlight.
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.
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.
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/>.
20 ///////////////////////////////////////////////////////////////////////////
22 // File and Version Information:
23 // $Rev:: 156 $: revision of last commit
24 // $Author:: odjuvsla $: author of last commit
25 // $Date:: 2013-10-06 16:17:52 +0200 #$: date of last commit
31 ///////////////////////////////////////////////////////////////////////////
38 #include "randomgenerator.h"
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.
52 // For more information see the Mersenne Twistor homepage
53 // http://www.math.keio.ac.jp/~matumoto/emt.html
55 // Advantage: large period 2**19937-1
57 // (only two times slower than TRandom, but
58 // two times faster than TRandom2)
59 // Drawback: a relative large internal state of 624 integers
62 // Aug.99 ROOT implementation based on CLHEP by P.Malzacher
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 */
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 */
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 /////////////////////////////////////////////////////////////////////
84 void randomGenerator::SetSeed(unsigned int seed)
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
94 Lockguard<MutexPosix> guard(&_mutex);
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);
108 double randomGenerator::Rndom(int)
111 // Machine independent random number generator.
112 // Produces uniformly-distributed floating points in ]0,1]
113 // Method: Mersenne Twistor
115 Lockguard<MutexPosix> guard(&_mutex);
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;
127 if (_count624 >= kN) {
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);
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);
140 y = (_Mt[kN-1] & kUpperMask) | (_Mt[0] & kLowerMask);
141 _Mt[kN-1] = _Mt[kM-1] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0);
145 y = _Mt[_count624++];
147 y ^= ((y << 7 ) & kTemperingMaskB );
148 y ^= ((y << 15) & kTemperingMaskC );
151 if (y) return ( (double) y * 2.3283064365386963e-10); // * Power(2,-32)