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/* |
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A C-program for MT19937, with initialization improved 2002/1/26. |
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Coded by Takuji Nishimura and Makoto Matsumoto. |
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|
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Before using, initialize the state by using init_genrand(seed) |
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or init_by_array(init_key, key_length). |
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|
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Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, |
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All rights reserved. |
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|
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions |
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are met: |
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|
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1. Redistributions of source code must retain the above copyright |
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notice, this list of conditions and the following disclaimer. |
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|
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2. Redistributions in binary form must reproduce the above copyright |
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notice, this list of conditions and the following disclaimer in the |
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documentation and/or other materials provided with the distribution. |
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|
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3. The names of its contributors may not be used to endorse or promote |
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products derived from this software without specific prior written |
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permission. |
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|
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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|
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|
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Any feedback is very welcome. |
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http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html |
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email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space) |
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|
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$Id$ |
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*/ |
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|
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#include "rng_mt.h" |
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|
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/* Period parameters */ |
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#define N 624 |
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#define M 397 |
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#define MATRIX_A 0x9908b0dfUL /* constant vector a */ |
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#define UPPER_MASK 0x80000000UL /* most significant w-r bits */ |
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#define LOWER_MASK 0x7fffffffUL /* least significant r bits */ |
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|
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static unsigned long mt[N]; /* the array for the state vector */ |
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static int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */ |
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|
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/* initializes mt[N] with a seed */ |
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void |
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init_genrand(unsigned long s) |
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{ |
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mt[0] = s & 0xffffffffUL; |
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|
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for (mti = 1; mti < N; mti++) |
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{ |
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mt[mti] = (1812433253UL * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti); |
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/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ |
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/* In the previous versions, MSBs of the seed affect */ |
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/* only MSBs of the array mt[]. */ |
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/* 2002/01/09 modified by Makoto Matsumoto */ |
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mt[mti] &= 0xffffffffUL; |
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/* for >32 bit machines */ |
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} |
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} |
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|
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/* initialize by an array with array-length */ |
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/* init_key is the array for initializing keys */ |
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/* key_length is its length */ |
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/* slight change for C++, 2004/2/26 */ |
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void |
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init_by_array(unsigned long init_key[], int key_length) |
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{ |
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int i, j, k; |
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|
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init_genrand(19650218UL); |
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|
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i = 1; j = 0; |
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k = (N > key_length ? N : key_length); |
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|
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for (; k; k--) |
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{ |
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mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525UL)) |
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+ init_key[j] + j; /* non linear */ |
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mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ |
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i++; j++; |
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|
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if (i >= N) |
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{ |
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mt[0] = mt[N - 1]; |
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i = 1; |
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} |
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|
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if (j >= key_length) |
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j = 0; |
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} |
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|
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for (k = N - 1; k; k--) |
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{ |
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mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) |
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- i; /* non linear */ |
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mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ |
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i++; |
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|
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if (i >= N) |
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{ |
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mt[0] = mt[N - 1]; |
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i = 1; |
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} |
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} |
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|
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mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */ |
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} |
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|
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/* generates a random number on [0,0xffffffff]-interval */ |
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unsigned long |
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genrand_int32(void) |
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{ |
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unsigned long y; |
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static unsigned long mag01[2]={ 0x0UL, MATRIX_A }; |
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/* mag01[x] = x * MATRIX_A for x=0,1 */ |
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|
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if (mti >= N) |
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{ /* generate N words at one time */ |
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int kk; |
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|
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if (mti == N + 1) /* if init_genrand() has not been called, */ |
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init_genrand(5489UL); /* a default initial seed is used */ |
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|
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for (kk = 0; kk < N - M; kk++) |
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{ |
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y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK); |
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mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1UL]; |
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} |
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|
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for (; kk < N - 1; kk++) |
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{ |
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y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK); |
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mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1UL]; |
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} |
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|
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y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK); |
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mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1UL]; |
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|
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mti = 0; |
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} |
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|
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y = mt[mti++]; |
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|
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/* Tempering */ |
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y ^= (y >> 11); |
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y ^= (y << 7) & 0x9d2c5680UL; |
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y ^= (y << 15) & 0xefc60000UL; |
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y ^= (y >> 18); |
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|
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return y; |
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} |