core: add random number generator
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core/mt19937.c
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243
core/mt19937.c
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/*
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A C-program for MT19937-64 (2004/9/29 version).
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Coded by Takuji Nishimura and Makoto Matsumoto.
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This is a 64-bit version of Mersenne Twister pseudorandom number
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generator.
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Before using, initialize the state by using init_genrand64(seed)
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or init_by_array64(init_key, key_length).
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Copyright (C) 2004, Makoto Matsumoto and Takuji Nishimura,
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All rights reserved.
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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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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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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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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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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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References:
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T. Nishimura, ``Tables of 64-bit Mersenne Twisters''
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ACM Transactions on Modeling and
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Computer Simulation 10. (2000) 348--357.
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M. Matsumoto and T. Nishimura,
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``Mersenne Twister: a 623-dimensionally equidistributed
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uniform pseudorandom number generator''
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ACM Transactions on Modeling and
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Computer Simulation 8. (Jan. 1998) 3--30.
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Any feedback is very welcome.
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http://www.math.hiroshima-u.ac.jp/~m-mat/MT/emt.html
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email: m-mat @ math.sci.hiroshima-u.ac.jp (remove spaces)
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*/
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#include "random.h"
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#include <blue/core/random.h>
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#define NN 312
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#define MM 156
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#define MATRIX_A 0xB5026F5AA96619E9ULL
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#define UM 0xFFFFFFFF80000000ULL /* Most significant 33 bits */
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#define LM 0x7FFFFFFFULL /* Least significant 31 bits */
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/* initializes mt[NN] with a seed */
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static void init_genrand64(struct b_random_ctx *context, unsigned long long seed)
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{
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context->__mt19937.mt[0] = seed;
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for (context->__mt19937.mti = 1; context->__mt19937.mti < NN;
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context->__mt19937.mti++)
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context->__mt19937.mt[context->__mt19937.mti]
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= (6364136223846793005ULL
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* (context->__mt19937.mt[context->__mt19937.mti - 1]
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^ (context->__mt19937
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.mt[context->__mt19937.mti - 1]
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>> 62))
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+ context->__mt19937.mti);
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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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static void init_by_array64(
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struct b_random_ctx *context, unsigned long long init_key[],
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unsigned long long key_length)
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{
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unsigned long long i, j, k;
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init_genrand64(context, 19650218ULL);
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i = 1;
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j = 0;
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k = (NN > key_length ? NN : key_length);
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for (; k; k--) {
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context->__mt19937.mt[i]
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= (context->__mt19937.mt[i]
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^ ((context->__mt19937.mt[i - 1]
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^ (context->__mt19937.mt[i - 1] >> 62))
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* 3935559000370003845ULL))
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+ init_key[j] + j; /* non linear */
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i++;
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j++;
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if (i >= NN) {
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context->__mt19937.mt[0] = context->__mt19937.mt[NN - 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 = NN - 1; k; k--) {
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context->__mt19937.mt[i]
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= (context->__mt19937.mt[i]
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^ ((context->__mt19937.mt[i - 1]
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^ (context->__mt19937.mt[i - 1] >> 62))
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* 2862933555777941757ULL))
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- i; /* non linear */
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i++;
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if (i >= NN) {
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context->__mt19937.mt[0] = context->__mt19937.mt[NN - 1];
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i = 1;
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}
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}
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context->__mt19937.mt[0]
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= 1ULL << 63; /* MSB is 1; assuring non-zero initial array */
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}
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/* generates a random number on [0, 2^64-1]-interval */
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static unsigned long long genrand64_int64(struct b_random_ctx *context)
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{
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#if 0
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/* This is the original implementation. It is replaced by the alternate implementation, below. */
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int i;
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unsigned long long x;
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static unsigned long long mag01[2]={0ULL, MATRIX_A};
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if (mti >= NN) { /* generate NN words at one time */
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/* if init_genrand64() has not been called, */
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/* a default initial seed is used */
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if (mti == NN+1)
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init_genrand64(5489ULL);
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for (i=0;i<NN-MM;i++) {
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x = (mt[i]&UM)|(mt[i+1]&LM);
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mt[i] = mt[i+MM] ^ (x>>1) ^ mag01[(int)(x&1ULL)];
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}
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for (;i<NN-1;i++) {
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x = (mt[i]&UM)|(mt[i+1]&LM);
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mt[i] = mt[i+(MM-NN)] ^ (x>>1) ^ mag01[(int)(x&1ULL)];
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}
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x = (mt[NN-1]&UM)|(mt[0]&LM);
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mt[NN-1] = mt[MM-1] ^ (x>>1) ^ mag01[(int)(x&1ULL)];
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mti = 0;
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}
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x = mt[mti++];
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x ^= (x >> 29) & 0x5555555555555555ULL;
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x ^= (x << 17) & 0x71D67FFFEDA60000ULL;
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x ^= (x << 37) & 0xFFF7EEE000000000ULL;
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x ^= (x >> 43);
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return x;
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#else
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/* This is the altered Cocoa with Love implementation. */
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size_t i;
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size_t j;
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unsigned long long result;
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if (context->__mt19937.mti >= NN) { /* generate NN words at one time */
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size_t mid = NN / 2;
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unsigned long long stateMid = context->__mt19937.mt[mid];
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unsigned long long x;
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unsigned long long y;
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/* NOTE: this "untwist" code is modified from the original to
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* improve performance, as described here:
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* http://www.cocoawithlove.com/blog/2016/05/19/random-numbers.html
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* These modifications are offered for use under the original
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* icense at the top of this file.
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*/
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for (i = 0, j = mid; i != mid - 1; i++, j++) {
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x = (context->__mt19937.mt[i] & UM)
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context->__mt19937.mt[i]
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= context->__mt19937.mt[i + mid] ^ (x >> 1)
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^ ((context->__mt19937.mt[i + 1] & 1) * MATRIX_A);
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y = (context->__mt19937.mt[j] & UM)
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context->__mt19937.mt[j]
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= context->__mt19937.mt[j - mid] ^ (y >> 1)
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^ ((context->__mt19937.mt[j + 1] & 1) * MATRIX_A);
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}
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x = (context->__mt19937.mt[mid - 1] & UM) | (stateMid & LM);
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context->__mt19937.mt[mid - 1] = context->__mt19937.mt[NN - 1]
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^ (x >> 1)
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^ ((stateMid & 1) * MATRIX_A);
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y = (context->__mt19937.mt[NN - 1] & UM)
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context->__mt19937.mt[NN - 1]
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= context->__mt19937.mt[mid - 1] ^ (y >> 1)
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^ ((context->__mt19937.mt[0] & 1) * MATRIX_A);
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context->__mt19937.mti = 0;
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}
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result = context->__mt19937.mt[context->__mt19937.mti];
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context->__mt19937.mti = context->__mt19937.mti + 1;
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result ^= (result >> 29) & 0x5555555555555555ULL;
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result ^= (result << 17) & 0x71D67FFFEDA60000ULL;
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result ^= (result << 37) & 0xFFF7EEE000000000ULL;
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result ^= (result >> 43);
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return result;
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#endif
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}
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/* generates a random number on [0,1]-real-interval */
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double genrand64_real1(struct b_random_ctx *context)
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{
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return (genrand64_int64(context) >> 11) * (1.0 / 9007199254740991.0);
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}
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/* generates a random number on [0,1)-real-interval */
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double genrand64_real2(struct b_random_ctx *context)
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{
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return (genrand64_int64(context) >> 11) * (1.0 / 9007199254740992.0);
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}
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/* generates a random number on (0,1)-real-interval */
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double genrand64_real3(struct b_random_ctx *context)
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{
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return ((genrand64_int64(context) >> 12) + 0.5)
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* (1.0 / 4503599627370496.0);
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}
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struct b_random_algorithm z__b_gen_mt19937 = {
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.gen_name = "mt19937",
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.gen_init = init_genrand64,
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.gen_getrand = genrand64_int64,
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};
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