On Fri, Dec 9, 2011 at 7:50 AM, Alexander Epifanov <[email protected]>wrote:
> Hello,
>
> I made my first application on J.
> I was surprised that it works faster than K:
>
> pip =: 256 #. x:@:".;._2@:,&'.'
> ips =: pip"1 (_1&}.;._2 (1!:1<'ips.txt'))
> iprs =: |:pip;._1 "1 (','&,)"1 (_1&}.;._2 (1!:1<'ipr.txt'))
> i =: /:{.iprs
> l =: i{{.iprs
> r =: i{{:iprs
> m =: 0,(>./ @: {.&r)"0 (1+i.#l)
> f =: <: m {~ I.~&l
> 6!:2 'f"1 ips'
>
> But I suppose that it could be better:
> 1) It uses x:, but IP address could fill int, I found that J does not
> support unsigned int (K also).
> But unfortunately, I cannot find the way in J how to convert 4 numbers
> into signed int i J.
>
Why are you concerned about data representation type? This works fine:
pip =: 256 #. ".;._2@:,&'.'
>
> 2) How is it possible to change m =: 0,(>./ @: {.&r)"0 (1+i.#l)
> without right brackets? I expected something like ... "0 @: 1 + i.#l,
> but it does not work. I think that "0 +&1 i.#l is not best solution.
>
I do not have any ipr.txt so I do not know what domain m is intended for.
I could guess, but right now I do not understand your question.
> 3) ips =: pip"1 (_1&}.;._2 (1!:1<'ips.txt')) is very slow, in pip
> function, is it possible to make it faster?
>
Getting rid of x: should make pip faster. I also suspect you want
something like this:
ips=: pip;._2 (1!:1 <'ips.txt') -. CR
Or:
ips=: 256 #. 0&".;._2 ' ' (I.@e.&('.',CR)@])} 1!:1<'ips.txt'
> 4) I cannot find in VOC is I. binary search or something like that?
>
Typically, yes.
--
Raul
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