2 A C-program for MT19937, with initialization improved 2002/1/26.
3 Coded by Takuji Nishimura and Makoto Matsumoto.
5 Before using, initialize the state by using init_genrand(seed)
6 or init_by_array(init_key, key_length).
8 Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
11 Redistribution and use in source and binary forms, with or without
12 modification, are permitted provided that the following conditions
15 1. Redistributions of source code must retain the above copyright
16 notice, this list of conditions and the following disclaimer.
18 2. Redistributions in binary form must reproduce the above copyright
19 notice, this list of conditions and the following disclaimer in the
20 documentation and/or other materials provided with the distribution.
22 3. The names of its contributors may not be used to endorse or promote
23 products derived from this software without specific prior written
26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
29 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
30 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 Any feedback is very welcome.
40 http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
41 email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
47 /* Period parameters */
50 #define MATRIX_A 0x9908b0dfUL /* constant vector a */
51 #define UPPER_MASK 0x80000000UL /* most significant w-r bits */
52 #define LOWER_MASK 0x7fffffffUL /* least significant r bits */
54 static unsigned long mt[N]; /* the array for the state vector */
55 static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */
57 /* initializes mt[N] with a seed */
58 static void init_genrand(unsigned long s)
60 mt[0]= s & 0xffffffffUL;
61 for (mti=1; mti<N; mti++) {
63 (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
64 /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
65 /* In the previous versions, MSBs of the seed affect */
66 /* only MSBs of the array mt[]. */
67 /* 2002/01/09 modified by Makoto Matsumoto */
68 mt[mti] &= 0xffffffffUL;
69 /* for >32 bit machines */
73 /* initialize by an array with array-length */
74 /* init_key is the array for initializing keys */
75 /* key_length is its length */
76 /* slight change for C++, 2004/2/26 */
77 static void init_by_array(unsigned long init_key[], int key_length)
80 init_genrand(19650218UL);
82 k = (N>key_length ? N : key_length);
84 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL))
85 + init_key[j] + j; /* non linear */
86 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
88 if (i>=N) { mt[0] = mt[N-1]; i=1; }
89 if (j>=key_length) j=0;
92 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL))
94 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
96 if (i>=N) { mt[0] = mt[N-1]; i=1; }
99 mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
102 /* generates a random number on [0,0xffffffff]-interval */
103 uint32_t genrand_int32(void) {
105 static unsigned long mag01[2]={0x0UL, MATRIX_A};
106 /* mag01[x] = x * MATRIX_A for x=0,1 */
108 if (mti >= N) { /* generate N words at one time */
111 if (mti == N+1) /* if init_genrand() has not been called, */
112 init_genrand(5489UL); /* a default initial seed is used */
114 for (kk=0;kk<N-M;kk++) {
115 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
116 mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
119 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
120 mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
122 y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
123 mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
132 y ^= (y << 7) & 0x9d2c5680UL;
133 y ^= (y << 15) & 0xefc60000UL;
139 uint64_t genrand_int64(void) {
142 x = genrand_int32(); y = genrand_int32();
146 void init_mersenne(void) {
147 unsigned long init[4]={0x123, 0x234, 0x345, 0x456}, length=4;
148 init_by_array(init, length);