80d9be86e6
Even though we're not incorrect about operator precedence, let's add some parens in some particularly confusing places to placate GCC 4.3 so that we don't have to turn the warning off. Agreed that this is a bit of a pain for those users who get the order of operations correct, but it is likely to prevent bugs in certain cases.
149 lines
4.5 KiB
C++
149 lines
4.5 KiB
C++
/*
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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
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* 3. The names of its contributors may not be used to endorse or
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* promote products derived from this software without specific
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* prior written 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
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* 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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#include "base/random.hh"
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/* initializes mt[N] with a seed */
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void
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Random::init(uint32_t s)
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{
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mti = N + 1;
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mt[0] = s & (uint32_t)0xffffffff;
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for (mti = 1; mti < N; mti++) {
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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] &= (uint32_t)0xffffffff;
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/* for >32 bit machines */
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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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Random::init(uint32_t init_key[], int key_length)
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{
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int i = 1;
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int j = 0;
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int k = (N > key_length) ? N : key_length;
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init(19650218);
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for (; k; k--) {
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mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * (uint32_t)1664525))
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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++;
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j++;
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if (i >= N) {
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mt[0] = mt[N - 1];
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i = 1;
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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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for (k = N - 1; k; k--) {
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/* non linear */
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mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941UL)) - i;
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/* for WORDSIZE > 32 machines */
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mt[i] &= (uint32_t)0xffffffff;
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i++;
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if (i >= N) {
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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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/* MSB is 1; assuring non-zero initial array */
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mt[0] = (uint32_t)0x80000000;
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}
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/* generates a random number on [0,0xffffffff]-interval */
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uint32_t
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Random::genrand()
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{
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uint32_t y;
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static uint32_t mag01[2] = { 0, MATRIX_A};
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if (mti >= N) { /* generate N words at one time */
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int kk;
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for (kk = 0; kk < N - M; kk++) {
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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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for (; kk < N - 1; kk++) {
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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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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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mti = 0;
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}
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y = mt[mti++];
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/* Tempering */
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y ^= (y >> 11);
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y ^= (y << 7) & (uint32_t)0x9d2c5680;
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y ^= (y << 15) & (uint32_t)0xefc60000;
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y ^= (y >> 18);
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return y;
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}
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