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.keio.ac.jp/matumoto/emt.html
41 email: matumoto@math.keio.ac.jp
42 */
43
44 /* Period parameters */
45 #define N 624
46 #define M 397
47 #define MATRIX_A 0x9908b0dfUL /* constant vector a */
48 #define UPPER_MASK 0x80000000UL /* most significant w-r bits */
49 #define LOWER_MASK 0x7fffffffUL /* least significant r bits */
50
51 static unsigned long mt[N]; /* the array for the state vector */
52 static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */
53
54 /* initializes mt[N] with a seed */
init_genrand(unsigned long s)55 void init_genrand(unsigned long s)
56 {
57 mt[0]= s & 0xffffffffUL;
58 for (mti=1; mti<N; mti++) {
59 mt[mti] =
60 (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
61 /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
62 /* In the previous versions, MSBs of the seed affect */
63 /* only MSBs of the array mt[]. */
64 /* 2002/01/09 modified by Makoto Matsumoto */
65 mt[mti] &= 0xffffffffUL;
66 /* for >32 bit machines */
67 }
68 }
69
70 /* initialize by an array with array-length */
71 /* init_key is the array for initializing keys */
72 /* key_length is its length */
init_by_array(init_key,key_length)73 void init_by_array(init_key, key_length)
74 unsigned long init_key[], key_length;
75 {
76 int i, j, k;
77 init_genrand(19650218UL);
78 i=1; j=0;
79 k = (N>key_length ? N : key_length);
80 for (; k; k--) {
81 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL))
82 + init_key[j] + j; /* non linear */
83 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
84 i++; j++;
85 if (i>=N) { mt[0] = mt[N-1]; i=1; }
86 if (j>=key_length) j=0;
87 }
88 for (k=N-1; k; k--) {
89 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL))
90 - i; /* non linear */
91 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
92 i++;
93 if (i>=N) { mt[0] = mt[N-1]; i=1; }
94 }
95
96 mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
97 }
98
99 /* generates a random number on [0,0xffffffff]-interval */
genrand_int32(void)100 unsigned long genrand_int32(void)
101 {
102 unsigned long y;
103 static unsigned long mag01[2]={0x0UL, MATRIX_A};
104 /* mag01[x] = x * MATRIX_A for x=0,1 */
105
106 if (mti >= N) { /* generate N words at one time */
107 int kk;
108
109 if (mti == N+1) /* if init_genrand() has not been called, */
110 init_genrand(5489UL); /* a default initial seed is used */
111
112 for (kk=0;kk<N-M;kk++) {
113 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
114 mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
115 }
116 for (;kk<N-1;kk++) {
117 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
118 mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
119 }
120 y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
121 mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
122
123 mti = 0;
124 }
125
126 y = mt[mti++];
127
128 /* Tempering */
129 y ^= (y >> 11);
130 y ^= (y << 7) & 0x9d2c5680UL;
131 y ^= (y << 15) & 0xefc60000UL;
132 y ^= (y >> 18);
133
134 return y;
135 }
136
137 /* generates a random number on [0,0x7fffffff]-interval */
genrand_int31(void)138 long genrand_int31(void)
139 {
140 return (long)(genrand_int32()>>1);
141 }
142
143 /* generates a random number on [0,1]-real-interval */
genrand_real1(void)144 double genrand_real1(void)
145 {
146 return genrand_int32()*(1.0/4294967295.0);
147 /* divided by 2^32-1 */
148 }
149
150 /* generates a random number on [0,1)-real-interval */
genrand_real2(void)151 double genrand_real2(void)
152 {
153 return genrand_int32()*(1.0/4294967296.0);
154 /* divided by 2^32 */
155 }
156
157 /* generates a random number on (0,1)-real-interval */
genrand_real3(void)158 double genrand_real3(void)
159 {
160 return (((double)genrand_int32()) + 0.5)*(1.0/4294967296.0);
161 /* divided by 2^32 */
162 }
163
164 /* generates a random number on [0,1) with 53-bit resolution*/
genrand_res53(void)165 double genrand_res53(void)
166 {
167 unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6;
168 return(a*67108864.0+b)*(1.0/9007199254740992.0);
169 }
170 /* These real versions are due to Isaku Wada, 2002/01/09 added */
171