TUPLE: mersenne-twister { seq uint-array } { i fixnum } ;
-: mt-n 624 ; inline
-: mt-m 397 ; inline
-: mt-a HEX: 9908b0df ; inline
+CONSTANT: n 624
+CONSTANT: m 397
+CONSTANT: a uint-array{ 0 HEX: 9908b0df }
-: wrap-nth ( n seq -- obj )
- [ length mod ] keep nth-unsafe ; inline
+: y ( n seq -- y )
+ [ nth-unsafe 31 mask-bit ]
+ [ [ 1 + ] [ nth-unsafe ] bi* 31 bits ] 2bi bitor ; inline
-: set-wrap-nth ( obj n seq -- )
- [ length mod ] keep set-nth-unsafe ; inline
-
-: calculate-y ( n seq -- y )
- [ wrap-nth 31 mask-bit ]
- [ [ 1+ ] [ wrap-nth ] bi* 31 bits ] 2bi bitor ; inline
-
-: (mt-generate) ( n seq -- next-mt )
+: mt[k] ( offset n seq -- )
[
- calculate-y
- [ 2/ ] [ odd? mt-a 0 ? ] bi bitxor
- ] [
- [ mt-m + ] [ wrap-nth ] bi*
- ] 2bi bitxor ; inline
+ [ [ + ] dip nth-unsafe ]
+ [ y [ 2/ ] [ 1 bitand a nth ] bi bitxor ] 2bi
+ bitxor
+ ] 2keep set-nth-unsafe ; inline
: mt-generate ( mt -- )
[
- mt-n swap seq>> '[
- _ [ (mt-generate) ] [ set-wrap-nth ] 2bi
- ] each
+ 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 wrap-nth dup -30 shift bitxor 1812433253 * + 1+ 32 bits ; inline
+ dupd nth dup -30 shift bitxor 1812433253 * + 1 + 32 bits ; inline
: init-mt-rest ( seq -- )
- mt-n 1- swap '[
- _ [ init-mt-formula ] [ [ 1+ ] dip set-wrap-nth ] 2bi
+ n 1 - swap '[
+ _ [ init-mt-formula ] [ [ 1 + ] dip set-nth ] 2bi
] each ; inline
: init-mt-seq ( seed -- seq )
- 32 bits mt-n <uint-array>
- [ set-first ] [ init-mt-rest ] [ ] tri ;
+ 32 bits n <uint-array>
+ [ set-first ] [ init-mt-rest ] [ ] tri ; inline
: mt-temper ( y -- yt )
dup -11 shift bitxor
dup -18 shift bitxor ; inline
: next-index ( mt -- i )
- dup i>> dup mt-n < [ nip ] [ drop mt-generate 0 ] if ; inline
+ dup i>> dup n < [ nip ] [ drop mt-generate 0 ] if ; inline
PRIVATE>
M: mersenne-twister random-32* ( mt -- r )
[ next-index ]
- [ seq>> wrap-nth mt-temper ]
- [ [ 1+ ] change-i drop ] tri ;
-
-USE: init
+ [ seq>> nth-unsafe mt-temper ]
+ [ [ 1 + ] change-i drop ] tri ;
[
[ 32 random-bits ] with-system-random