74 lines
1.9 KiB
Factor
74 lines
1.9 KiB
Factor
! Copyright (C) 2005 Doug Coleman.
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! See http://factor.sf.net/license.txt for BSD license.
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! mersenne twister based on
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! http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/CODES/mt19937ar.c
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! usage: 1000 [ drop genrand . ] each
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! initializes to seed 5489 automatically
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IN: crypto
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USING: kernel math namespaces sequences ;
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: N 624 ; inline
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: M 397 ; inline
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: A HEX: 9908b0df ; inline
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: HI-MASK HEX: 80000000 ; inline
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: LO-MASK HEX: 7fffffff ; inline
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SYMBOL: init
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SYMBOL: mt
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SYMBOL: mti
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: odd? ( n -- )
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1 bitand 0 > ; inline
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: mt-nth ( n -- nth )
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mt get nth ; inline
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: (formula) ( mt mti magic -- mt[mti] )
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-rot dup rot nth dup -30 shift bitxor rot * + HEX: ffffffff bitand ; inline
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: (y) ( index -- y )
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dup 1+ mt-nth LO-MASK bitand >r mt-nth HI-MASK bitand r> bitor ; inline
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: (set-mt-ith) ( y index index1 -- )
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mt-nth rot dup odd? [ A ] [ 0 ] if swap -1 shift bitxor bitxor swap mt get set-nth ; inline
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: (temper) ( y -- yt )
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dup -11 shift bitxor
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dup 7 shift HEX: 9d2c5680 bitand bitxor
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dup 15 shift HEX: efc60000 bitand bitxor
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dup -18 shift bitxor ; inline
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: (generate-new-mt)
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N M - [ dup (y) over dup M + (set-mt-ith) ] repeat
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M 1 - [ dup 227 + dup (y) over dup M N - + (set-mt-ith) drop ] repeat
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0 mti set ;
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: init-genrand ( seed -- )
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init on
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[ N 1- [ drop 0 , ] each ] { } make swap
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HEX: ffffffff bitand 0 pick set-nth
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N 1- [ 2dup 1812433253 (formula) 1+ pick pick 1+ swap set-nth ] repeat
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mt set 0 mti set
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(generate-new-mt) ;
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: genrand ( -- rand )
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init get [ 5489 init-genrand ] unless
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mti get N >= [
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(generate-new-mt)
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] when
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mti get mt get nth
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mti [ 1+ ] change
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(temper) ;
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USE: compiler
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USE: test
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: million-genrand 1000000 [ drop genrand drop ] each ;
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: test-genrand \ million-genrand compile [ million-genrand ] time ;
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! test-genrand
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! 5987 ms run / 56 ms GC time
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