! 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: arrays kernel math namespaces sequences system init
-accessors math.ranges random circular math.bitfields.lib
-combinators ;
+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
+CONSTANT: n 624
+CONSTANT: m 397
+CONSTANT: a uint-array{ 0 HEX: 9908b0df }
-: calculate-y ( n seq -- y )
- [ nth 32 mask-bit ]
- [ [ 1+ ] [ nth ] bi* 31 bits ] 2bi bitor ; inline
+: y ( n seq -- y )
+ [ nth-unsafe 31 mask-bit ]
+ [ [ 1 + ] [ nth-unsafe ] 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 + ] [ nth ] bi*
- ] 2bi bitxor ;
+ [ [ + ] 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-nth ] 2bi
- ] curry each
- ] [ 0 >>i drop ] bi ;
+ 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 ;
+ dupd nth dup -30 shift bitxor 1812433253 * + 1 + 32 bits ; inline
: init-mt-rest ( seq -- )
- mt-n 1- swap [
- [ init-mt-formula ] [ >r 1+ r> set-nth ] 2bi
- ] curry each ;
+ n 1 - swap '[
+ _ [ init-mt-formula ] [ [ 1 + ] dip set-nth ] 2bi
+ ] each ; inline
: init-mt-seq ( seed -- seq )
- 32 bits mt-n 0 <array> <circular>
- [ 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 ;
+ dup i>> dup n < [ nip ] [ drop mt-generate 0 ] if ; inline
PRIVATE>
M: mersenne-twister random-32* ( mt -- r )
[ next-index ]
- [ seq>> nth mt-temper ]
- [ [ 1+ ] change-i drop ] tri ;
+ [ seq>> nth-unsafe mt-temper ]
+ [ [ 1 + ] change-i drop ] tri ;
+
+[
+ [ 32 random-bits ] with-system-random
+ <mersenne-twister> random-generator set-global
+] "bootstrap.random" add-init-hook