From thomas@biostat.washington.edu  Fri Mar 26 16:29:29 1999
From: thomas@biostat.washington.edu (Thomas Lumley)
Date: Fri, 26 Mar 1999 08:29:29 -0800 (PST)
Subject: linear search
In-Reply-To: <99Mar26.110423est.13493@mailgate.bank-banque-canada.ca>
Message-ID: <Pine.GSO.4.10.9903260824130.2767-100000@wompom.biostat.washington.edu>

On Fri, 26 Mar 1999, Paul Gilbert wrote:

> Doug Bates writes:
> >... Also, the search to resolve a name is a linear search over the
> >available names.  ...
> 
> Does anyone have an idea of how series a problem this is with large packages. R
> still runs slower than Splus 3.3 for me, and I wonder how big a part of the
> problem this is?

A very limited profiling experiment about a year ago (so out of date as
well as limited) suggested that perhaps 15-30% of R's time is spent in the
linear search functions when running the survival4 test suite.

We do intend to implement hashing for name lookup fairly soon. It should
make a noticeable difference, especially with huge libraries like lme
(over 500 functions) loaded.

The relative speed of R and S-PLUS is very problem-dependent, so it's hard
to make any reliable predictions.

	-thomas


-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._


linear search
Thomas Lumley