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/*
* This is based on trimmed version of MT19937. To get the original version,
* contact <http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html>.
*
* The original copyright notice follows.
*
* A C-program for MT19937, with initialization improved 2002/2/10.
* Coded by Takuji Nishimura and Makoto Matsumoto.
* This is a faster version by taking Shawn Cokus's optimization,
* Matthe Bellew's simplification, Isaku Wada's real version.
*
* Before using, initialize the state by using init_genrand(mt, seed)
* or init_by_array(mt, init_key, key_length).
*
* Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. The names of its contributors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* Any feedback is very welcome.
* http://www.math.keio.ac.jp/matumoto/emt.html
* email: matumoto@math.keio.ac.jp
*/
#include <limits.h>
typedef int int_must_be_32bit_at_least[sizeof(int) * CHAR_BIT < 32 ? -1 : 1];
/* Period parameters */
#define N 624
#define M 397
#define MATRIX_A 0x9908b0dfU /* constant vector a */
#define UMASK 0x80000000U /* most significant w-r bits */
#define LMASK 0x7fffffffU /* least significant r bits */
#define MIXBITS(u,v) ( ((u) & UMASK) | ((v) & LMASK) )
#define TWIST(u,v) ((MIXBITS(u,v) >> 1) ^ ((v)&1U ? MATRIX_A : 0U))
enum {MT_MAX_STATE = N};
struct MT {
/* assume int is enough to store 32bits */
unsigned int state[N]; /* the array for the state vector */
unsigned int *next;
int left;
};
#define genrand_initialized(mt) ((mt)->next != 0)
#define uninit_genrand(mt) ((mt)->next = 0)
/* initializes state[N] with a seed */
static void
init_genrand(struct MT *mt, unsigned int s)
{
int j;
mt->state[0] = s & 0xffffffffU;
for (j=1; j<N; j++) {
mt->state[j] = (1812433253U * (mt->state[j-1] ^ (mt->state[j-1] >> 30)) + j);
/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
/* In the previous versions, MSBs of the seed affect */
/* only MSBs of the array state[]. */
/* 2002/01/09 modified by Makoto Matsumoto */
mt->state[j] &= 0xffffffff; /* for >32 bit machines */
}
mt->left = 1;
mt->next = mt->state + N;
}
/* initialize by an array with array-length */
/* init_key is the array for initializing keys */
/* key_length is its length */
/* slight change for C++, 2004/2/26 */
static void
init_by_array(struct MT *mt, unsigned int init_key[], int key_length)
{
int i, j, k;
init_genrand(mt, 19650218U);
i=1; j=0;
k = (N>key_length ? N : key_length);
for (; k; k--) {
mt->state[i] = (mt->state[i] ^ ((mt->state[i-1] ^ (mt->state[i-1] >> 30)) * 1664525U))
+ init_key[j] + j; /* non linear */
mt->state[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
i++; j++;
if (i>=N) { mt->state[0] = mt->state[N-1]; i=1; }
if (j>=key_length) j=0;
}
for (k=N-1; k; k--) {
mt->state[i] = (mt->state[i] ^ ((mt->state[i-1] ^ (mt->state[i-1] >> 30)) * 1566083941U))
- i; /* non linear */
mt->state[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
i++;
if (i>=N) { mt->state[0] = mt->state[N-1]; i=1; }
}
mt->state[0] = 0x80000000U; /* MSB is 1; assuring non-zero initial array */
}
static void
next_state(struct MT *mt)
{
unsigned int *p = mt->state;
int j;
/* if init_genrand() has not been called, */
/* a default initial seed is used */
if (!genrand_initialized(mt)) init_genrand(mt, 5489U);
mt->left = N;
mt->next = mt->state;
for (j=N-M+1; --j; p++)
*p = p[M] ^ TWIST(p[0], p[1]);
for (j=M; --j; p++)
*p = p[M-N] ^ TWIST(p[0], p[1]);
*p = p[M-N] ^ TWIST(p[0], mt->state[0]);
}
/* generates a random number on [0,0xffffffff]-interval */
static unsigned int
genrand_int32(struct MT *mt)
{
unsigned int y;
if (--mt->left <= 0) next_state(mt);
y = *mt->next++;
/* Tempering */
y ^= (y >> 11);
y ^= (y << 7) & 0x9d2c5680;
y ^= (y << 15) & 0xefc60000;
y ^= (y >> 18);
return y;
}
/* generates a random number on [0,1) with 53-bit resolution*/
static double
genrand_real(struct MT *mt)
{
unsigned int a = genrand_int32(mt)>>5, b = genrand_int32(mt)>>6;
return(a*67108864.0+b)*(1.0/9007199254740992.0);
}
/* generates a random number on [0,1] with 53-bit resolution*/
// TODO
#define genrand_real2 genrand_real
/* These real versions are due to Isaku Wada, 2002/01/09 added */
#undef N
#undef M
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