62 lines
1.7 KiB
Factor
62 lines
1.7 KiB
Factor
USING: kernel math errors namespaces math-contrib sequences io ;
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USE: prettyprint
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USE: inspector
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IN: crypto
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SYMBOL: a
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SYMBOL: n
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SYMBOL: r
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SYMBOL: s
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SYMBOL: composite
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SYMBOL: count
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SYMBOL: trials
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: rand[1..n-1] ( n -- )
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1- random-int 1+ ;
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: (factor-2s) ( s n -- s n )
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dup 2 mod 0 = [ -1 shift >r 1+ r> (factor-2s) ] when ;
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: factor-2s ( n -- r s )
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#! factor an even number into 2 ^ s * m
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dup dup even? >r 0 > r> and [
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"input must be positive and even" throw
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] unless 0 swap (factor-2s) ;
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: init-miller-rabin ( n -- )
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0 composite set
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[ n set ] keep 10000 < 20 100 ? trials set ;
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: miller-rabin ( n -- bool )
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[
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init-miller-rabin
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n get even? [
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f ] [
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n get 1- factor-2s s set r set
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trials get [
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n get rand[1..n-1] a set
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a get s get n get ^mod 1 = [
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0 count set
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r get [
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2 over ^ s get * a get swap n get ^mod n get - -1 = [
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count [ 1+ ] change
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r get +
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] when
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] repeat
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count get zero? [
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composite on
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trials get +
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] when
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] unless
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] repeat
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composite get 0 = [ t ] [ composite get not ] if
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] if
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] with-scope ;
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: next-miller-rabin-prime ( n -- p )
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dup even? [ 1+ ] [ 2 + ] if
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dup miller-rabin [ next-miller-rabin-prime ] unless ;
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! 473155932665450549999756893736999469773678960651272093993257221235459777950185377130233556540099119926369437865330559863 100 miller-rabin
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