Re: [R] need fast [lt]apply ()

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Subject: Re: [R] need fast [lt]apply ()
From: Prof Brian D Ripley (ripley@stats.ox.ac.uk)
Date: Wed 22 Dec 1999 - 02:58:26 EST


Message-ID: <Pine.GSO.4.05.9912211648410.6353-100000@auk.stats>

On Tue, 21 Dec 1999, Martin Maechler wrote:

[...]

> I hope this reminds more people than just me
> that we (R users) "desperately" need someone who
>
> rewrites apply(),lapply(), and tapply()
> to become much faster (as they are with S-plus [34].y, but not 5.[12])...

I think the problem was S-PLUS 5.0r[123]: 5.1's [ltr]apply seem fast again.

The key is to write a fast internal lapply and use that for the others.

> Anyone working on this ?

No, but as the .Call introduction has a cut-down version, I might as
well take a look.

Actually, I misread: outer is quite slow but it does not use apply!

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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