00001 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> 00002 <!-- saved from url=(0046)http://www.math.keio.ac.jp/~matumoto/mt19937.c --> 00003 <HTML><HEAD> 00004 <META content="text/html; charset=windows-1250" http-equiv=Content-Type> 00005 <META content="MSHTML 5.00.3315.2870" name=GENERATOR></HEAD> 00006 <BODY><XMP>/* A C-program for MT19937: Real number version */ 00007 /* genrand() generates one pseudorandom real number (double) */ 00008 /* which is uniformly distributed on [0,1]-interval, for each */ 00009 /* call. sgenrand(seed) set initial values to the working area */ 00010 /* of 624 words. Before genrand(), sgenrand(seed) must be */ 00011 /* called once. (seed is any 32-bit integer except for 0). */ 00012 /* Integer generator is obtained by modifying two lines. */ 00013 /* Coded by Takuji Nishimura, considering the suggestions by */ 00014 /* Topher Cooper and Marc Rieffel in July-Aug. 1997. */ 00015 00016 /* This library is free software; you can redistribute it and/or */ 00017 /* modify it under the terms of the GNU Library General Public */ 00018 /* License as published by the Free Software Foundation; either */ 00019 /* version 2 of the License, or (at your option) any later */ 00020 /* version. */ 00021 /* This library is distributed in the hope that it will be useful, */ 00022 /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ 00023 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. */ 00024 /* See the GNU Library General Public License for more details. */ 00025 /* You should have received a copy of the GNU Library General */ 00026 /* Public License along with this library; if not, write to the */ 00027 /* Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA */ 00028 /* 02111-1307 USA */ 00029 00030 /* Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura. */ 00031 /* Any feedback is very welcome. For any question, comments, */ 00032 /* see http://www.math.keio.ac.jp/matumoto/emt.html or email */ 00033 /* matumoto@math.keio.ac.jp */ 00034 00035 #include<stdio.h> 00036 00037 /* Period parameters */ 00038 #define N 624 00039 #define M 397 00040 #define MATRIX_A 0x9908b0df /* constant vector a */ 00041 #define UPPER_MASK 0x80000000 /* most significant w-r bits */ 00042 #define LOWER_MASK 0x7fffffff /* least significant r bits */ 00043 00044 /* Tempering parameters */ 00045 #define TEMPERING_MASK_B 0x9d2c5680 00046 #define TEMPERING_MASK_C 0xefc60000 00047 #define TEMPERING_SHIFT_U(y) (y >> 11) 00048 #define TEMPERING_SHIFT_S(y) (y << 7) 00049 #define TEMPERING_SHIFT_T(y) (y << 15) 00050 #define TEMPERING_SHIFT_L(y) (y >> 18) 00051 00052 static unsigned long mt[N]; /* the array for the state vector */ 00053 static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */ 00054 00055 /* initializing the array with a NONZERO seed */ 00056 void 00057 sgenrand(seed) 00058 unsigned long seed; 00059 { 00060 /* setting initial seeds to mt[N] using */ 00061 /* the generator Line 25 of Table 1 in */ 00062 /* [KNUTH 1981, The Art of Computer Programming */ 00063 /* Vol. 2 (2nd Ed.), pp102] */ 00064 mt[0]= seed & 0xffffffff; 00065 for (mti=1; mti<N; mti++) 00066 mt[mti] = (69069 * mt[mti-1]) & 0xffffffff; 00067 } 00068 00069 double /* generating reals */ 00070 /* unsigned long */ /* for integer generation */ 00071 genrand() 00072 { 00073 unsigned long y; 00074 static unsigned long mag01[2]={0x0, MATRIX_A}; 00075 /* mag01[x] = x * MATRIX_A for x=0,1 */ 00076 00077 if (mti >= N) { /* generate N words at one time */ 00078 int kk; 00079 00080 if (mti == N+1) /* if sgenrand() has not been called, */ 00081 sgenrand(4357); /* a default initial seed is used */ 00082 00083 for (kk=0;kk<N-M;kk++) { 00084 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); 00085 mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1]; 00086 } 00087 for (;kk<N-1;kk++) { 00088 y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); 00089 mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1]; 00090 } 00091 y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK); 00092 mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1]; 00093 00094 mti = 0; 00095 } 00096 00097 y = mt[mti++]; 00098 y ^= TEMPERING_SHIFT_U(y); 00099 y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B; 00100 y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C; 00101 y ^= TEMPERING_SHIFT_L(y); 00102 00103 return ( (double)y / (unsigned long)0xffffffff ); /* reals */ 00104 /* return y; */ /* for integer generation */ 00105 } 00106 00107 /* this main() outputs first 1000 generated numbers */ 00108 main() 00109 { 00110 int j; 00111 00112 sgenrand(4357); /* any nonzero integer can be used as a seed */ 00113 for (j=0; j<1000; j++) { 00114 printf("%5f ", genrand()); 00115 if (j%8==7) printf("\n"); 00116 } 00117 printf("\n"); 00118 } 00119 </XMP></BODY></HTML>
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