! 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 system init
-accessors math.ranges random circular math.bitwise
-combinators specialized-arrays.uint ;
+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 i ;
+TUPLE: mersenne-twister { seq uint-array } { i fixnum } ;
: mt-n 624 ; inline
: mt-m 397 ; 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 )
- [ nth 31 mask-bit ]
- [ [ 1+ ] [ nth ] bi* 31 bits ] 2bi bitor ; inline
+ [ wrap-nth 31 mask-bit ]
+ [ [ 1+ ] [ wrap-nth ] bi* 31 bits ] 2bi bitor ; inline
: (mt-generate) ( n seq -- next-mt )
[
calculate-y
[ 2/ ] [ odd? mt-a 0 ? ] bi bitxor
] [
- [ mt-m + ] [ nth ] bi*
- ] 2bi bitxor ;
+ [ mt-m + ] [ wrap-nth ] bi*
+ ] 2bi bitxor ; inline
: mt-generate ( mt -- )
[
- mt-n swap seq>> [
- [ (mt-generate) ] [ set-nth ] 2bi
- ] curry each
- ] [ 0 >>i drop ] bi ;
+ mt-n swap seq>> '[
+ _ [ (mt-generate) ] [ set-wrap-nth ] 2bi
+ ] each
+ ] [ 0 >>i drop ] bi ; inline
: 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 -- )
mt-n 1- swap [
- [ init-mt-formula ] [ [ 1+ ] dip set-nth ] 2bi
- ] curry each ;
+ [ init-mt-formula ] [ [ 1+ ] dip set-wrap-nth ] 2bi
+ ] curry each ; inline
: init-mt-seq ( seed -- seq )
- 32 bits mt-n <uint-array> <circular>
+ 32 bits mt-n <uint-array>
[ set-first ] [ init-mt-rest ] [ ] tri ;
: mt-temper ( y -- yt )
dup -18 shift bitxor ; inline
: 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>
M: mersenne-twister random-32* ( mt -- r )
[ next-index ]
- [ seq>> nth mt-temper ]
+ [ seq>> wrap-nth mt-temper ]
[ [ 1+ ] change-i drop ] tri ;
USE: init