mersenne_twister.cc (6130B)
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 */ 57 void init_genrand(unsigned long s) 58 { 59 mt[0]= s & 0xffffffffUL; 60 for (mti=1; mti<N; mti++) { 61 mt[mti] = 62 (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti); 63 /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ 64 /* In the previous versions, MSBs of the seed affect */ 65 /* only MSBs of the array mt[]. */ 66 /* 2002/01/09 modified by Makoto Matsumoto */ 67 mt[mti] &= 0xffffffffUL; 68 /* for >32 bit machines */ 69 } 70 } 71 72 /* initialize by an array with array-length */ 73 /* init_key is the array for initializing keys */ 74 /* key_length is its length */ 75 /* slight change for C++, 2004/2/26 */ 76 void init_by_array(unsigned long init_key[], int key_length) 77 { 78 int i, j, k; 79 init_genrand(19650218UL); 80 i=1; j=0; 81 k = (N>key_length ? N : key_length); 82 for (; k; k--) { 83 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL)) 84 + init_key[j] + j; /* non linear */ 85 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ 86 i++; j++; 87 if (i>=N) { mt[0] = mt[N-1]; i=1; } 88 if (j>=key_length) j=0; 89 } 90 for (k=N-1; k; k--) { 91 mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL)) 92 - i; /* non linear */ 93 mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ 94 i++; 95 if (i>=N) { mt[0] = mt[N-1]; i=1; } 96 } 97 98 mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */ 99 } 100 101 /* generates a random number on [0,0xffffffff]-interval */ 102 unsigned long genrand_int32(void) 103 { 104 unsigned long y; 105 static unsigned long mag01[2]={0x0UL, MATRIX_A}; 106 /* mag01[x] = x * MATRIX_A for x=0,1 */ 107 108 if (mti >= N) { /* generate N words at one time */ 109 int kk; 110 111 if (mti == N+1) /* if init_genrand() has not been called, */ 112 init_genrand(5489UL); /* a default initial seed is used */ 113 114 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]; 117 } 118 for (;kk<N-1;kk++) { 119 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); 120 mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL]; 121 } 122 y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK); 123 mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL]; 124 125 mti = 0; 126 } 127 128 y = mt[mti++]; 129 130 /* Tempering */ 131 y ^= (y >> 11); 132 y ^= (y << 7) & 0x9d2c5680UL; 133 y ^= (y << 15) & 0xefc60000UL; 134 y ^= (y >> 18); 135 136 return y; 137 } 138 139 /* generates a random number on [0,0x7fffffff]-interval */ 140 long genrand_int31(void) 141 { 142 return (long)(genrand_int32()>>1); 143 } 144 145 /* generates a random number on [0,1]-real-interval */ 146 double genrand_real1(void) 147 { 148 return genrand_int32()*(1.0/4294967295.0); 149 /* divided by 2^32-1 */ 150 } 151 152 /* generates a random number on [0,1)-real-interval */ 153 double genrand_real2(void) 154 { 155 return genrand_int32()*(1.0/4294967296.0); 156 /* divided by 2^32 */ 157 } 158 159 /* generates a random number on (0,1)-real-interval */ 160 double genrand_real3(void) 161 { 162 return (((double)genrand_int32()) + 0.5)*(1.0/4294967296.0); 163 /* divided by 2^32 */ 164 } 165 166 /* generates a random number on [0,1) with 53-bit resolution*/ 167 double genrand_res53(void) 168 { 169 unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6; 170 return(a*67108864.0+b)*(1.0/9007199254740992.0); 171 } 172 /* These real versions are due to Isaku Wada, 2002/01/09 added */ 173 174 int main(void) 175 { 176 int i; 177 unsigned long init[4]={0x123, 0x234, 0x345, 0x456}, length=4; 178 init_by_array(init, length); 179 for( i = 0; i < 10000000; i++ ) { 180 int x = genrand_int32(); 181 printf( "%d\n", x ); 182 } 183 return 0; 184 }