From ggrothendieck at gmail.com  Fri Jul 28 20:12:15 2006
From: ggrothendieck at gmail.com (Gabor Grothendieck)
Date: Fri, 28 Jul 2006 14:12:15 -0400
Subject: [Rd] Any interest in "merge" and "by" implementations
	specifically for sorted data?
In-Reply-To: <FFDE23C5-EA11-4E16-B372-012DB00BD589@sympatico.ca>
References: <Pine.GSO.4.31.0607280805550.24504-100000@markov.stats>
	<FFDE23C5-EA11-4E16-B372-012DB00BD589@sympatico.ca>
Message-ID: <971536df0607281112j43c4ffc0s96d3b4743b93b690@mail.gmail.com>

There was a performance comparison of several moving average
approaches here:
http://tolstoy.newcastle.edu.au/R/help/04/10/5161.html

The author of that message ultimately wrote the caTools R package
which contains some optimized versions.

Not sure if these results suggest anything of interest here but it
would be interesting if various base routines could be sped up
to the point that a simple idiom is competitive with the caTools versions.


On 7/28/06, Kevin B. Hendricks <kevin.hendricks at sympatico.ca> wrote:
> Hi,
>
> I was using my installed R which is 2.3.1 for the first tests.  I
> moved to the r-devel tree (I svn up and rebuild everyday) for my "by"
> tests to see if it would work any better.  I neglected to retest
> "merge" with the devel version.
>
> So it appears "merge" is already fixed and I just need to worry about
> "by".
>
> On Jul 28, 2006, at 3:06 AM, Brian D Ripley wrote:
>
> > Which version of R are you looking at?   R-devel has
> >
> >     o merge() works more efficiently when there are relatively few
> >       matches between the data frames (for example, for 1-1
> >       matching).  The order of the result is changed for 'sort = FALSE'.
> >
>
> Thanks,
>
> Kevin
>
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> https://stat.ethz.ch/mailman/listinfo/r-devel
>



[Rd] Any interest in "merge" and "by" implementations specifically for sorted data?
Gabor Grothendieck