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#include <stdio.h> | |
/* Period parameters */ | |
#define N 624 | |
#define M 397 | |
#define MATRIX_A 0x9908b0dfUL /* constant vector a */ | |
#define UPPER_MASK 0x80000000UL /* most significant w-r bits */ | |
#define LOWER_MASK 0x7fffffffUL /* least significant r bits */ | |
static unsigned long mt[N]; /* the array for the state vector */ | |
static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */ | |
void init_genrand(unsigned long s) | |
{ | |
mt[0]= s & 0xffffffffUL; | |
for (mti=1; mti<N; mti++) { | |
mt[mti] = (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti); | |
mt[mti] &= 0xffffffffUL; | |
} | |
} | |
unsigned long temper(unsigned long y) | |
{ | |
y ^= (y >> 11); | |
y ^= (y << 7) & 0x9d2c5680UL; | |
y ^= (y << 15) & 0xefc60000UL; | |
y ^= (y >> 18); | |
return y; | |
} | |
/* | |
genrand_int32の実装3通り | |
それぞれで変数mtiの意味が違ってくるので注意 | |
*/ | |
/* ナイーブな実装 (数列の最後のN項を順番にmtに格納しておく方法) */ | |
unsigned long genrand_int32_naive(void) | |
{ | |
unsigned long y; | |
static unsigned long mag01[2]={0x0UL, MATRIX_A}; | |
unsigned long last = mt[0]; | |
/* 配列の要素を一つ左へずらす */ | |
for (int i = 0; i < N - 1; i ++) { | |
mt[i] = mt[i+1]; | |
} | |
y = (last&UPPER_MASK)|(mt[0]&LOWER_MASK); | |
mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL]; | |
return temper(mt[N-1]); | |
} | |
/* ラウンドロビン法 (ずらす代わりにmt[mti-k]に数列の最後から数えてk番目の値をいれる) */ | |
unsigned long genrand_int32_roundrobin(void) | |
{ | |
unsigned long y; | |
static unsigned long mag01[2]={0x0UL, MATRIX_A}; | |
y = (mt[mti % N]&UPPER_MASK)|(mt[(mti+1)%N]&LOWER_MASK); | |
y = mt[mti % N] = mt[(mti+M)%N] ^ (y >> 1) ^ mag01[y & 0x1UL]; | |
mti = (mti + 1) % N; | |
return temper(y); | |
} | |
/* オリジナルの実装 (N回に一回テーブルを更新する) */ | |
unsigned long genrand_int32_orig(void) | |
{ | |
unsigned long y; | |
static unsigned long mag01[2]={0x0UL, MATRIX_A}; | |
if (mti >= N) { | |
int kk; | |
for (kk=0;kk<N-M;kk++) { | |
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); | |
mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL]; | |
} | |
for (;kk<N-1;kk++) { | |
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK); | |
mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL]; | |
} | |
y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK); | |
mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL]; | |
mti = 0; | |
} | |
y = mt[mti++]; | |
return temper(y); | |
} | |
/* どの実装でも同じ結果になることを確認 */ | |
int main(void) | |
{ | |
int n = 10; | |
init_genrand(0); | |
for (int i=0; i<n; i++) { | |
printf("%08x ", genrand_int32_naive()); | |
} | |
printf("\n"); | |
init_genrand(0); | |
for (int i=0; i<n; i++) { | |
printf("%08x ", genrand_int32_roundrobin()); | |
} | |
printf("\n"); | |
init_genrand(0); | |
for (int i=0; i<n; i++) { | |
printf("%08x ", genrand_int32_orig()); | |
} | |
printf("\n"); | |
return 0; | |
} |
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