Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

file 178 lines (156 sloc) 5.986 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178
/*
* 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
Something went wrong with that request. Please try again.