Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 9169 | turbocat | 1 | /* |
| 2 | Copyright (C) 1997--2004, Makoto Matsumoto, Takuji Nishimura, and |
||
| 3 | Eric Landry; All rights reserved. |
||
| 4 | |||
| 5 | Redistribution and use in source and binary forms, with or without |
||
| 6 | modification, are permitted provided that the following conditions |
||
| 7 | are met: |
||
| 8 | |||
| 9 | 1. Redistributions of source code must retain the above copyright |
||
| 10 | notice, this list of conditions and the following disclaimer. |
||
| 11 | |||
| 12 | 2. Redistributions in binary form must reproduce the above copyright |
||
| 13 | notice, this list of conditions and the following disclaimer |
||
| 14 | in the documentation and/or other materials provided with the |
||
| 15 | distribution. |
||
| 16 | |||
| 17 | 3. The names of its contributors may not be used to endorse or |
||
| 18 | promote products derived from this software without specific |
||
| 19 | prior written permission. |
||
| 20 | |||
| 21 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
||
| 22 | "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
||
| 23 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
||
| 24 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
||
| 25 | OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
||
| 26 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
||
| 27 | LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
||
| 28 | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
||
| 29 | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
||
| 30 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
||
| 31 | OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
||
| 32 | |||
| 33 | Any feedback is very welcome. |
||
| 34 | http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html |
||
| 35 | email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space) |
||
| 36 | |||
| 37 | Reference: M. Matsumoto and T. Nishimura, "Mersenne Twister: |
||
| 38 | A 623-Dimensionally Equidistributed Uniform Pseudo-Random Number |
||
| 39 | Generator", ACM Transactions on Modeling and Computer Simulation, |
||
| 40 | Vol. 8, No. 1, January 1998, pp 3--30. |
||
| 41 | */ |
||
| 42 | |||
| 43 | #include "mtrand.h" |
||
| 44 | |||
| 45 | /* Period parameters */ |
||
| 46 | #define N 624 |
||
| 47 | #define M 397 |
||
| 48 | #define MATRIX_A 0x9908b0dfUL /* constant vector a */ |
||
| 49 | #define UPPER_MASK 0x80000000UL /* most significant w-r bits */ |
||
| 50 | #define LOWER_MASK 0x7fffffffUL /* least significant r bits */ |
||
| 51 | |||
| 52 | static unsigned long x[N]; /* the array for the state vector */ |
||
| 53 | static unsigned long *p0, *p1, *pm; |
||
| 54 | |||
| 55 | void mt_srand( unsigned long s ) |
||
| 56 | { |
||
| 57 | int i; |
||
| 58 | |||
| 59 | x[0] = s & 0xffffffffUL; |
||
| 60 | for (i = 1; i < N; ++i) { |
||
| 61 | x[i] = (1812433253UL * (x[i - 1] ^ (x[i - 1] >> 30)) + i) |
||
| 62 | & 0xffffffffUL; /* for >32 bit machines */ |
||
| 63 | } |
||
| 64 | p0 = x; |
||
| 65 | p1 = x + 1; |
||
| 66 | pm = x + M; |
||
| 67 | } |
||
| 68 | |||
| 69 | /* generates a random number on the interval [0,0xffffffff] */ |
||
| 70 | unsigned long mt_rand( void ) |
||
| 71 | { |
||
| 72 | unsigned long y; |
||
| 73 | |||
| 74 | if (!p0) { |
||
| 75 | /* Default seed */ |
||
| 76 | mt_srand(5489UL); |
||
| 77 | } |
||
| 78 | /* Twisted feedback */ |
||
| 79 | y = *p0 = *pm++ ^ (((*p0 & UPPER_MASK) | (*p1 & LOWER_MASK)) >> 1) ^ ((~(*p1 & 1)+1) & MATRIX_A); |
||
| 80 | p0 = p1++; |
||
| 81 | if (pm == x + N) { |
||
| 82 | pm = x; |
||
| 83 | } |
||
| 84 | if (p1 == x + N) { |
||
| 85 | p1 = x; |
||
| 86 | } |
||
| 87 | /* Temper */ |
||
| 88 | y ^= y >> 11; |
||
| 89 | y ^= y << 7 & 0x9d2c5680UL; |
||
| 90 | y ^= y << 15 & 0xefc60000UL; |
||
| 91 | y ^= y >> 18; |
||
| 92 | return y; |
||
| 93 | } |
||
| 94 | |||
| 95 | /* generates a random number on the interval [0,1]. */ |
||
| 96 | float mt_rand_1( void ) |
||
| 97 | { |
||
| 98 | return ((float)mt_rand() / (float)MT_RAND_MAX); |
||
| 99 | } |
||
| 100 | |||
| 101 | /* generates a random number on the interval [0,1). */ |
||
| 102 | float mt_rand_lt1( void ) |
||
| 103 | { |
||
| 104 | /* MT_RAND_MAX must be a float before adding one to it! */ |
||
| 105 | return ((float)mt_rand() / ((float)MT_RAND_MAX + 1.0f)); |
||
| 106 | } |
||
| 107 |