| /* |
| * A C-program for MT19937, with initialization improved 2002/1/26. |
| * Coded by Takuji Nishimura and Makoto Matsumoto. |
| * |
| * Before using, initialize the state by using init_genrand(seed) |
| * or init_by_array(init_key, key_length). |
| * |
| * Copyright (C) 1997-2002 Makoto Matsumoto and Takuji Nishimura |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * 3. The names of its contributors may not be used to endorse or |
| * promote products derived from this software without specific |
| * prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| * |
| * Any feedback is very welcome. |
| * http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html |
| * email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space) |
| */ |
| |
| #include "base/random.hh" |
| |
| /* initializes mt[N] with a seed */ |
| void |
| Random::init(uint32_t s) |
| { |
| mti = N + 1; |
| mt[0] = s & (uint32_t)0xffffffff; |
| |
| for (mti = 1; mti < N; mti++) { |
| mt[mti] = 1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti; |
| /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ |
| /* In the previous versions, MSBs of the seed affect */ |
| /* only MSBs of the array mt[]. */ |
| /* 2002/01/09 modified by Makoto Matsumoto */ |
| mt[mti] &= (uint32_t)0xffffffff; |
| /* for >32 bit machines */ |
| } |
| } |
| |
| /* initialize by an array with array-length */ |
| /* init_key is the array for initializing keys */ |
| /* key_length is its length */ |
| /* slight change for C++, 2004/2/26 */ |
| void |
| Random::init(uint32_t init_key[], int key_length) |
| { |
| int i = 1; |
| int j = 0; |
| int k = (N > key_length) ? N : key_length; |
| |
| init(19650218); |
| |
| for (; k; k--) { |
| mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * (uint32_t)1664525)) |
| + init_key[j] + j; /* non linear */ |
| |
| mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ |
| |
| i++; |
| j++; |
| |
| if (i >= N) { |
| mt[0] = mt[N - 1]; |
| i = 1; |
| } |
| |
| if (j >= key_length) |
| j = 0; |
| } |
| |
| for (k = N - 1; k; k--) { |
| /* non linear */ |
| mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) - i; |
| |
| /* for WORDSIZE > 32 machines */ |
| mt[i] &= (uint32_t)0xffffffff; |
| i++; |
| |
| if (i >= N) { |
| mt[0] = mt[N - 1]; |
| i = 1; |
| } |
| } |
| |
| /* MSB is 1; assuring non-zero initial array */ |
| mt[0] = (uint32_t)0x80000000; |
| } |
| |
| /* generates a random number on [0,0xffffffff]-interval */ |
| uint32_t |
| Random::genrand() |
| { |
| uint32_t y; |
| static uint32_t mag01[2] = { 0, MATRIX_A}; |
| |
| if (mti >= N) { /* generate N words at one time */ |
| 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++]; |
| |
| /* Tempering */ |
| y ^= (y >> 11); |
| y ^= (y << 7) & (uint32_t)0x9d2c5680; |
| y ^= (y << 15) & (uint32_t)0xefc60000; |
| y ^= (y >> 18); |
| |
| return y; |
| } |