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Diffstat (limited to 'intern/keymaker/mt19937int.c')
| -rw-r--r-- | intern/keymaker/mt19937int.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/intern/keymaker/mt19937int.c b/intern/keymaker/mt19937int.c new file mode 100644 index 00000000000..7845f9ad56e --- /dev/null +++ b/intern/keymaker/mt19937int.c @@ -0,0 +1,130 @@ +/* A C-program for MT19937: Integer version (1999/10/28) */ + +/* genrand() generates one pseudorandom unsigned integer (32bit) */ +/* which is uniformly distributed among 0 to 2^32-1 for each */ +/* call. sgenrand(seed) sets initial values to the working area */ +/* of 624 words. Before genrand(), sgenrand(seed) must be */ +/* called once. (seed is any 32-bit integer.) */ +/* Coded by Takuji Nishimura, considering the suggestions by */ +/* Topher Cooper and Marc Rieffel in July-Aug. 1997. */ + +/* This library is free software under the Artistic license: */ +/* see the file COPYING distributed together with this code. */ +/* For the verification of the code, its output sequence file */ +/* mt19937int.out is attached (2001/4/2) */ + +/* Copyright (C) 1997, 1999 Makoto Matsumoto and Takuji Nishimura. */ +/* Any feedback is very welcome. For any question, comments, */ +/* see http://www.math.keio.ac.jp/matumoto/emt.html or email */ +/* matumoto@math.keio.ac.jp */ + +/* REFERENCE */ +/* M. Matsumoto and T. Nishimura, */ +/* "Mersenne Twister: A 623-Dimensionally Equidistributed Uniform */ +/* Pseudo-Random Number Generator", */ +/* ACM Transactions on Modeling and Computer Simulation, */ +/* Vol. 8, No. 1, January 1998, pp 3--30. */ + +#include<stdio.h> + +#include "mt19937int.h" + +/* Period parameters */ +#define N 624 +#define M 397 +#define MATRIX_A 0x9908b0df /* constant vector a */ +#define UPPER_MASK 0x80000000 /* most significant w-r bits */ +#define LOWER_MASK 0x7fffffff /* least significant r bits */ + +/* Tempering parameters */ +#define TEMPERING_MASK_B 0x9d2c5680 +#define TEMPERING_MASK_C 0xefc60000 +#define TEMPERING_SHIFT_U(y) (y >> 11) +#define TEMPERING_SHIFT_S(y) (y << 7) +#define TEMPERING_SHIFT_T(y) (y << 15) +#define TEMPERING_SHIFT_L(y) (y >> 18) + +static unsigned long mt[N]; /* the array for the state vector */ +static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */ + +/* Initializing the array with a seed */ +void sgenrand(signed long seed) +{ + int i; + + for (i=0;i<N;i++) { + mt[i] = seed & 0xffff0000; + seed = 69069 * seed + 1; + mt[i] |= (seed & 0xffff0000) >> 16; + seed = 69069 * seed + 1; + } + mti = N; +} + +/* Initialization by "sgenrand()" is an example. Theoretically, */ +/* there are 2^19937-1 possible states as an intial state. */ +/* This function allows to choose any of 2^19937-1 ones. */ +/* Essential bits in "seed_array[]" is following 19937 bits: */ +/* (seed_array[0]&UPPER_MASK), seed_array[1], ..., seed_array[N-1]. */ +/* (seed_array[0]&LOWER_MASK) is discarded. */ +/* Theoretically, */ +/* (seed_array[0]&UPPER_MASK), seed_array[1], ..., seed_array[N-1] */ +/* can take any values except all zeros. */ +void lsgenrand(unsigned long *seed_array) + /* the length of seed_array[] must be at least N */ +{ + int i; + + for (i=0;i<N;i++) + mt[i] = seed_array[i]; + mti=N; +} + +unsigned long genrand() +{ + unsigned long y; + static unsigned long mag01[2]={0x0, MATRIX_A}; + /* mag01[x] = x * MATRIX_A for x=0,1 */ + + if (mti >= N) { /* generate N words at one time */ + int kk; + + if (mti == N+1) /* if sgenrand() has not been called, */ + sgenrand(4357); /* a default initial seed is used */ + + for (kk=0;kk<N-M;kk++) { + y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); + mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1]; + } + for (;kk<N-1;kk++) { + y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); + mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1]; + } + y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK); + mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1]; + + mti = 0; + } + + y = mt[mti++]; + y ^= TEMPERING_SHIFT_U(y); + y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B; + y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C; + y ^= TEMPERING_SHIFT_L(y); + + return y; +} + +/* This main() outputs first 1000 generated numbers. */ +/* +main() +{ + int i; + + sgenrand(4357); + for (i=0; i<1000; i++) { + printf("%10lu ", genrand()); + if (i%5==4) printf("\n"); + } +} +*/ |