[REBOL] Re: Speed testing prime functions..
From: joel:neely:fedex at: 28-Nov-2001 18:47
Hi, again, Ladislav,
Ladislav Mecir wrote:
> use [d] [
> d: [2 3 5 7]
> prime?: function [p] [c s l] [
> l: to integer! square-root p
> foreach v d [
> if p // v = 0 [return p = v]
> if v >= l [return true]
> ]
> c: (last d) + s: 6 - ((last d) // 3 * 2)
> while [c <= l] [
> if prime? c [
> append d c
> if p // c = 0 [return false]
> ]
> c: c + s: 6 - s
> ]
> true
> ]
> ]
>
Niceness restored!!
After I made the point earlier about testing only thru
the square root of the candidate, I'm glad you caught
my omission of that in the latter functions!
-jn-
--
; sub REBOL {}; sub head ($) {@_[0]}
REBOL []
# despam: func [e] [replace replace/all e ":" "." "#" "@"]
; sub despam {my ($e) = @_; $e =~ tr/:#/.@/; return "\n$e"}
print head reverse despam "moc:xedef#yleen:leoj" ;
