! Copyright (C) 2005, 2008 Doug Coleman. ! See http://factorcode.org/license.txt for BSD license. ! mersenne twister based on ! http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c USING: accessors alien.c-types alien.data fry init kernel math math.bitwise namespaces random sequences sequences.private specialized-arrays system ; SPECIALIZED-ARRAY: uint IN: random.mersenne-twister <PRIVATE TUPLE: mersenne-twister { seq uint-array } { i fixnum } ; CONSTANT: n 624 CONSTANT: m 397 CONSTANT: a uint-array{ 0 0x9908b0df } : mt-step ( k+m k+1 k seq -- ) [ [ nth-unsafe ] curry tri@ [ 31 bits ] [ 31 mask-bit ] bi* bitor [ 2/ ] [ 1 bitand a nth ] bi bitxor bitxor ] 2keep set-nth-unsafe ; inline : mt-steps ( k+m k+1 k n seq -- ) [ mt-step ] curry [ 3keep [ 1 + ] tri@ ] curry times 3drop ; inline : mt-generate ( mt -- ) [ seq>> [ [ m 1 0 n m - ] dip mt-steps ] [ [ 0 n m - 1 + n m - m 1 - ] dip mt-steps ] [ [ m 1 - 0 n 1 - ] dip mt-step ] tri ] [ 0 >>i drop ] bi ; inline : init-mt-formula ( i seq -- f(seq[i]) ) dupd nth dup -30 shift bitxor 1812433253 * + 1 w+ ; inline : init-mt-rest ( seq -- ) n 1 - swap '[ _ [ init-mt-formula ] [ [ 1 + ] dip set-nth ] 2bi ] each-integer ; inline : init-mt-seq ( seed -- seq ) 32 bits n uint <c-array> [ set-first ] [ init-mt-rest ] [ ] tri ; inline : mt-temper ( y -- yt ) dup -11 shift bitxor dup 7 shift 0x9d2c5680 bitand bitxor dup 15 shift 0xefc60000 bitand bitxor dup -18 shift bitxor ; inline : next-index ( mt -- i ) dup i>> dup n < [ nip ] [ drop mt-generate 0 ] if ; inline PRIVATE> : <mersenne-twister> ( seed -- obj ) init-mt-seq 0 mersenne-twister boa dup mt-generate ; M: mersenne-twister seed-random init-mt-seq >>seq dup mt-generate ; M: mersenne-twister random-32* [ next-index ] [ seq>> nth-unsafe mt-temper ] [ [ 1 + ] change-i drop ] tri ; : default-mersenne-twister ( -- mersenne-twister ) nano-count <mersenne-twister> ; [ default-mersenne-twister random-generator set-global ] "bootstrap.random" add-startup-hook