78 lines
2.0 KiB
Factor
78 lines
2.0 KiB
Factor
! 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: kernel math namespaces sequences sequences.private system
|
|
init accessors math.ranges random math.bitwise combinators
|
|
specialized-arrays.uint fry ;
|
|
IN: random.mersenne-twister
|
|
|
|
<PRIVATE
|
|
|
|
TUPLE: mersenne-twister { seq uint-array } { i fixnum } ;
|
|
|
|
: n 624 ; inline
|
|
: m 397 ; inline
|
|
: a uint-array{ 0 HEX: 9908b0df } ; inline
|
|
|
|
: y ( n seq -- y )
|
|
[ nth-unsafe 31 mask-bit ]
|
|
[ [ 1+ ] [ nth-unsafe ] bi* 31 bits ] 2bi bitor ; inline
|
|
|
|
: mt[k] ( offset n seq -- )
|
|
[
|
|
[ [ + ] dip nth-unsafe ]
|
|
[ y [ 2/ ] [ 1 bitand a nth ] bi bitxor ] 2bi
|
|
bitxor
|
|
] 2keep set-nth-unsafe ; inline
|
|
|
|
: mt-generate ( mt -- )
|
|
[
|
|
seq>>
|
|
[ [ n m - ] dip '[ [ m ] dip _ mt[k] ] each ]
|
|
[ [ m 1- ] dip '[ [ m n - ] [ n m - + ] bi* _ mt[k] ] each ]
|
|
bi
|
|
] [ 0 >>i drop ] bi ; inline
|
|
|
|
: init-mt-formula ( i seq -- f(seq[i]) )
|
|
dupd nth dup -30 shift bitxor 1812433253 * + 1+ 32 bits ; inline
|
|
|
|
: init-mt-rest ( seq -- )
|
|
n 1- swap '[
|
|
_ [ init-mt-formula ] [ [ 1+ ] dip set-nth ] 2bi
|
|
] each ; inline
|
|
|
|
: init-mt-seq ( seed -- seq )
|
|
32 bits n <uint-array>
|
|
[ set-first ] [ init-mt-rest ] [ ] tri ; inline
|
|
|
|
: mt-temper ( y -- yt )
|
|
dup -11 shift bitxor
|
|
dup 7 shift HEX: 9d2c5680 bitand bitxor
|
|
dup 15 shift HEX: efc60000 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 ( mt seed -- )
|
|
init-mt-seq >>seq drop ;
|
|
|
|
M: mersenne-twister random-32* ( mt -- r )
|
|
[ next-index ]
|
|
[ seq>> nth-unsafe mt-temper ]
|
|
[ [ 1+ ] change-i drop ] tri ;
|
|
|
|
USE: init
|
|
|
|
[
|
|
[ 32 random-bits ] with-system-random
|
|
<mersenne-twister> random-generator set-global
|
|
] "bootstrap.random" add-init-hook
|