small cleanup in miller-rabin

db4
Doug Coleman 2008-01-12 21:46:53 -10:00
parent 37544fe24e
commit f8a0d7403d
1 changed files with 2 additions and 7 deletions

View File

@ -20,17 +20,12 @@ SYMBOL: trials
: random-bits ( m -- n ) 2^ random ; foldable
: (factor-2s) ( s n -- s n )
dup even? [ -1 shift >r 1+ r> (factor-2s) ] when ;
: factor-2s ( n -- r s )
#! factor an even number into 2 ^ s * m
dup even? over 0 > and [
"input must be positive and even" throw
] unless 0 swap (factor-2s) ;
dup even? [ -1 shift >r 1+ r> factor-2s ] when ;
:: (miller-rabin) | n prime?! |
n 1- factor-2s s set r set
0 n 1- factor-2s s set r set
trials get [
n 1- [1,b] random a set
a get s get n ^mod 1 = [