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Faster mersenne-twister with specialized-arrays

db4
Slava Pestov 2008-12-03 10:44:41 -06:00
parent e6cb449b19
commit 378bedd1e0
1 changed files with 24 additions and 18 deletions
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42
basis/random/mersenne-twister/mersenne-twister.factor
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@ -2,48 +2,54 @@
! See http://factorcode.org/license.txt for BSD license. ! See http://factorcode.org/license.txt for BSD license.
! mersenne twister based on ! mersenne twister based on
! http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c ! http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c
USING: kernel math namespaces sequences system init USING: kernel math namespaces sequences sequences.private system
accessors math.ranges random circular math.bitwise init accessors math.ranges random math.bitwise combinators
combinators specialized-arrays.uint ; specialized-arrays.uint fry ;
IN: random.mersenne-twister IN: random.mersenne-twister
<PRIVATE <PRIVATE
TUPLE: mersenne-twister seq i ; TUPLE: mersenne-twister { seq uint-array } { i fixnum } ;
: mt-n 624 ; inline : mt-n 624 ; inline
: mt-m 397 ; inline : mt-m 397 ; inline
: mt-a HEX: 9908b0df ; inline : mt-a HEX: 9908b0df ; inline
: wrap-nth ( n seq -- obj )
[ length mod ] keep nth-unsafe ; inline
: set-wrap-nth ( obj n seq -- )
[ length mod ] keep set-nth-unsafe ; inline
: calculate-y ( n seq -- y ) : calculate-y ( n seq -- y )
[ nth 31 mask-bit ] [ wrap-nth 31 mask-bit ]
[ [ 1+ ] [ nth ] bi* 31 bits ] 2bi bitor ; inline [ [ 1+ ] [ wrap-nth ] bi* 31 bits ] 2bi bitor ; inline
: (mt-generate) ( n seq -- next-mt ) : (mt-generate) ( n seq -- next-mt )
[ [
calculate-y calculate-y
[ 2/ ] [ odd? mt-a 0 ? ] bi bitxor [ 2/ ] [ odd? mt-a 0 ? ] bi bitxor
] [ ] [
[ mt-m + ] [ nth ] bi* [ mt-m + ] [ wrap-nth ] bi*
] 2bi bitxor ; ] 2bi bitxor ; inline
: mt-generate ( mt -- ) : mt-generate ( mt -- )
[ [
mt-n swap seq>> [ mt-n swap seq>> '[
[ (mt-generate) ] [ set-nth ] 2bi _ [ (mt-generate) ] [ set-wrap-nth ] 2bi
] curry each ] each
] [ 0 >>i drop ] bi ; ] [ 0 >>i drop ] bi ; inline
: init-mt-formula ( i seq -- f(seq[i]) ) : init-mt-formula ( i seq -- f(seq[i]) )
dupd nth dup -30 shift bitxor 1812433253 * + 1+ 32 bits ; dupd wrap-nth dup -30 shift bitxor 1812433253 * + 1+ 32 bits ; inline
: init-mt-rest ( seq -- ) : init-mt-rest ( seq -- )
mt-n 1- swap [ mt-n 1- swap [
[ init-mt-formula ] [ [ 1+ ] dip set-nth ] 2bi [ init-mt-formula ] [ [ 1+ ] dip set-wrap-nth ] 2bi
] curry each ; ] curry each ; inline
: init-mt-seq ( seed -- seq ) : init-mt-seq ( seed -- seq )
32 bits mt-n <uint-array> <circular> 32 bits mt-n <uint-array>
[ set-first ] [ init-mt-rest ] [ ] tri ; [ set-first ] [ init-mt-rest ] [ ] tri ;
: mt-temper ( y -- yt ) : mt-temper ( y -- yt )
@ -53,7 +59,7 @@ TUPLE: mersenne-twister seq i ;
dup -18 shift bitxor ; inline dup -18 shift bitxor ; inline
: next-index ( mt -- i ) : next-index ( mt -- i )
dup i>> dup mt-n < [ nip ] [ drop mt-generate 0 ] if ; dup i>> dup mt-n < [ nip ] [ drop mt-generate 0 ] if ; inline
PRIVATE> PRIVATE>
@ -66,7 +72,7 @@ M: mersenne-twister seed-random ( mt seed -- )
M: mersenne-twister random-32* ( mt -- r ) M: mersenne-twister random-32* ( mt -- r )
[ next-index ] [ next-index ]
[ seq>> nth mt-temper ] [ seq>> wrap-nth mt-temper ]
[ [ 1+ ] change-i drop ] tri ; [ [ 1+ ] change-i drop ] tri ;
USE: init USE: init