1 /*
2 A C-program for MT19937, with initialization improved 2002/1/26.
3 Coded by Takuji Nishimura and Makoto Matsumoto.
4
5 Before using, initialize the state by using init_genrand(seed)
6 or init_by_array(init_key, key_length).
7
8 Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
9 All rights reserved.
10
11 Redistribution and use in source and binary forms, with or without
12 modification, are permitted provided that the following conditions
13 are met:
14
15 1. Redistributions of source code must retain the above copyright
16 notice, this list of conditions and the following disclaimer.
17
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.
21
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
24 permission.
25
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.
37
38
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)
42 */
43
44 #include <stdio.h>
45
46 /* Period parameters */
47 #define N 624
48 #define M 397
49 #define MATRIX_A 0x9908b0dfUL /* constant vector a */
50 #define UPPER_MASK 0x80000000UL /* most significant w-r bits */
51 #define LOWER_MASK 0x7fffffffUL /* least significant r bits */
52
53 static unsigned long mt[N]; /* the array for the state vector */
54 static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */
55
56 /* initializes mt[N] with a seed */
init_genrand(unsigned long s)57 void init_genrand(unsigned long s)
58 {
59 mt[0]= s & 0xffffffffUL;
60 for (mti=1; mti<N; mti++) {
61 mt[mti] = (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
62 /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
63 /* In the previous versions, MSBs of the seed affect */
64 /* only MSBs of the array mt[]. */
65 /* 2002/01/09 modified by Makoto Matsumoto */
66 mt[mti] &= 0xffffffffUL;
67 /* for >32 bit machines */
68 }
69 }
70
71 /* initialize by an array with array-length */
72 /* init_key is the array for initializing keys */
73 /* key_length is its length */
74 /* slight change for C++, 2004/2/26 */
init_by_array(unsigned long init_key[],int key_length)75 void init_by_array(unsigned long init_key[],int key_length)
76 {
77 int i, j, k;
78 init_genrand(19650218UL);
79 i=1; j=0;
80 k = (N>key_length ? N : key_length);
81 for (; k; k--) {
82 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL))
83 + init_key[j] + j; /* non linear */
84 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
85 i++; j++;
86 if (i>=N) { mt[0] = mt[N-1]; i=1; }
87 if (j>=key_length) j=0;
88 }
89 for (k=N-1; k; k--) {
90 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL))
91 - i; /* non linear */
92 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
93 i++;
94 if (i>=N) { mt[0] = mt[N-1]; i=1; }
95 }
96
97 mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
98 }
99
100 /* generates a random number on [0,0xffffffff]-interval */
genrand_int32(void)101 unsigned long genrand_int32(void)
102 {
103 unsigned long y;
104 static unsigned long mag01[2]={0x0UL, MATRIX_A};
105 /* mag01[x] = x * MATRIX_A for x=0,1 */
106
107 if (mti >= N) { /* generate N words at one time */
108 int kk;
109
110 if (mti == N+1) /* if init_genrand() has not been called, */
111 init_genrand(5489UL); /* a default initial seed is used */
112
113 for (kk=0;kk<N-M;kk++) {
114 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
115 mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
116 }
117 for (;kk<N-1;kk++) {
118 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
119 mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
120 }
121 y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
122 mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
123
124 mti = 0;
125 }
126
127 y = mt[mti++];
128
129 /* Tempering */
130 y ^= (y >> 11);
131 y ^= (y << 7) & 0x9d2c5680UL;
132 y ^= (y << 15) & 0xefc60000UL;
133 y ^= (y >> 18);
134
135 return y;
136 }
137
138 /* generates a random number on [0,0x7fffffff]-interval */
genrand_int31(void)139 long genrand_int31(void)
140 {
141 return (long)(genrand_int32()>>1);
142 }
143
144 /* generates a random number on [0,1]-real-interval */
genrand_real1(void)145 double genrand_real1(void)
146 {
147 return genrand_int32()*(1.0/4294967295.0);
148 /* divided by 2^32-1 */
149 }
150
151 /* generates a random number on [0,1)-real-interval */
genrand_real2(void)152 double genrand_real2(void)
153 {
154 return genrand_int32()*(1.0/4294967296.0);
155 /* divided by 2^32 */
156 }
157
158 /* generates a random number on (0,1)-real-interval */
genrand_real3(void)159 double genrand_real3(void)
160 {
161 return (((double)genrand_int32()) + 0.5)*(1.0/4294967296.0);
162 /* divided by 2^32 */
163 }
164
165 /* generates a random number on [0,1) with 53-bit resolution*/
genrand_res53(void)166 double genrand_res53(void)
167 {
168 unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6;
169 return(a*67108864.0+b)*(1.0/9007199254740992.0);
170 }
171