> [EMAIL PROTECTED] On Behalf Of Oleg Kobchenko
> Subject: RE: [Jprogramming] What a drag
>
> Wow. How is this exmpalined?
Using a symbolic verb (and nouns)...
lr'u'
'('"_ , [ , ' u '"_ , ] , ')'"_
(Y1;Y2;'..';YN)
+--+--+--+--+
|Y1|Y2|..|YN|
+--+--+--+--+
u e/\ (Y1;Y2;'..';YN)
+--+---------+----------------+-----------------------+
|Y1|(Y1 u Y2)|(Y1 u (Y2 u ..))|(Y1 u (Y2 u (.. u YN)))|
+--+---------+----------------+-----------------------+
(u~ e/\. &. |.) (Y1;Y2;'..';YN)
+--+---------+----------------+-----------------------+
|Y1|(Y1 u Y2)|((Y1 u Y2) u ..)|(((Y1 u Y2) u ..) u YN)|
+--+---------+----------------+-----------------------+
\. builds on previous results.
>
> Whereas
>
> Q=: _2+?1e6$5
> (+/\ -: +/\.&.|.) Q
> 1
> ts '+/\ Q'
> 0.00822809 4.19546e6
> ts '+/\.&.|. Q'
> 0.0244686 8.39014e6
J "knows" that + is associative so there is no advantage, on the contrary.
>
>
> --- Jose Mario Quintana <[EMAIL PROTECTED]> wrote:
>
> >
> > T=. ?1000$9
> > st'(([^:(0=]))/\) T'
> > 19136 2.13611842
> > st'(([^:(0=]))~/\. &. |.) T'
> > 11200 0.00382534652
> >
> > ((([^:(0=]))/\) -: (([^:(0=]))~/\. &. |.)) T
> > 1
> >
> >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED] [mailto:programming-
> > > [EMAIL PROTECTED] On Behalf Of Oleg Kobchenko
> > > Sent: Wednesday, December 13, 2006 12:38 PM
> > > To: Programming forum
> > > Subject: Re: [Jprogramming] What a drag
> > >
> > > That was a result of posing a question
> > > "How would a fast C code look like?" and
> > > then translated to J.
> > >
> > > Unfortunately, though it looks nice, it does not
> > > work fast in J. Whereas >./\ special coded,
> > > ([^:(0=]))/\ is not, although it is single scan tacit.
> > >
> > > As a result, more cumbersome multiscan algorithms
> > > perform faster.
> > >
> > >
> > > --- ramacd <[EMAIL PROTECTED]> wrote:
> > >
> > > > That is truly beautiful.
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Oleg Kobchenko" <[EMAIL PROTECTED]>
> > > > To: "Programming forum" <[email protected]>
> > > > Sent: Tuesday, December 12, 2006 4:31 AM
> > > > Subject: RE: [Jprogramming] What a drag
> > > >
> > > >
> > > > > More generally
> > > > >
> > > > > ([^:(0=]))/\ 5 4 0 0 5 0 3 0 0 0 7
> > > > > 5 4 4 4 5 5 3 3 3 3 7
> > > > >
> > > > >
> > > > > --- Oleg Kobchenko <[EMAIL PROTECTED]> wrote:
> > > > >
> > > > > > How about variation on the theme
> > > > > >
> > > > > > >./\ 3 4 0 0 5 0 6 0 0 0 7
> > > > > > 3 4 4 4 5 5 6 6 6 6 7
> > > > > >
> > > > > >
> > > > > > --- Dan Bron <[EMAIL PROTECTED]> wrote:
> > > > > >
> > > > > > > Raul wrote:
> > > > > > > > drag=: {~ [EMAIL PROTECTED] >./\@:* ([EMAIL PROTECTED]
> > > > > > > > 1{.0{.])
> > > > > > >
> > > > > > > Thank you; this is indeed faster; I've replaced my definition
> > > with
> > > > > > > yours. However, I was hoping for a solution that would
> complete
> > > in
> > > > > > > about half the time of the solutions I provided. That is, I'd
> > > like a
> > > > > > > 2x or 100% speedup; drag is only about 20% faster than
> drag0
> > > on my
> > > > > > > dataset.
> > > > > > >
> > > > > > > Any other lines of attack?
> > > > > > >
> > > > > > > -Dan
> > >
> > >
> > >
> > >
> > >
> __________________________________________________________________________
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>
>
>
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