From wsimpson@uwinnipeg.ca  Fri May 29 15:32:52 1998
From: wsimpson@uwinnipeg.ca (Bill Simpson)
Date: Fri, 29 May 1998 09:32:52 -0500 (CDT)
Subject: performance of apply
In-Reply-To: <6rlnrldvez.fsf@verdi.stat.wisc.edu>
Message-ID: <Pine.OSF.3.95.980529092504.31530A-100000@io.uwinnipeg.ca>

I was computing a function f(u,v) on bivariate point process data of
about 4500 points. The computation in R took about 96 hours (4 days!) on a
Pentium Pro 200 under linux with little or no other load. So I think speed
can be an issue, esp. when computing things one will eventually display
with image().

My collaborator and I wound up coding it in C and now the computation
takes 4 min (yes, 4 min vs 4 days).

Probably it could have been sped up in R but that would have taken the
same effort as coding in C, and the result would have been slower.

Bill Simpson

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performance of apply
Bill Simpson