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] = (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 */ 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 */ 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 */ 139 long genrand_int31(void) 140 { 141 return (long)(genrand_int32()>>1); 142 } 143 144 /* generates a random number on [0,1]-real-interval */ 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 */ 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 */ 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*/ 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
