From tlumley at uw.edu  Sun Dec 18 23:48:02 2011
From: tlumley at uw.edu (Thomas Lumley)
Date: Mon, 19 Dec 2011 11:48:02 +1300
Subject: [Rd] rowsum
In-Reply-To: <201103291256.p2TCuZOi004855@nemo.mayo.edu>
References: <201103291256.p2TCuZOi004855@nemo.mayo.edu>
Message-ID: <CAJ55+dKo+hy36YYSO3D+EGo74R2sEecwoENfW4J3fG-pOtGE=g@mail.gmail.com>

On Wed, Mar 30, 2011 at 1:56 AM, Terry Therneau <therneau at mayo.edu> wrote:
> ? ?> with the entirely different rowSums, but it has been around
> ? ?> for a long time.)
> ? ?A lot longer than rowSums ...
> ? ?> Bill Dunlap
> ? ?> Spotfire, TIBCO Software
> ? ?---
> ? ? ?This made me smile. ?The rowsums function was originally an internal
> ? ?part of the survival package, used for fast computation of certain sums
> ? ?when there is a cluster() statement. ?It was Statistical Sciences
> ? ?(S-Plus) who moved it to global status. ?That is, they used it in enough
> ? ?other places that they decided to speed it up, took over the
> ? ?maintainance and ownership of the function (with my blessing), and
> ? ?ceased to label it as part of "survival" in the manual.
> ? ? ?This "metabug" can't be laid at R's feet.

The same process happened independently in R.  I ported the 'survival'
version of rowsum() to R, added it to base R in version 0.63.1, and
later it made it faster using hashing.

So perhaps it isn't entirely StatSci's fault, although it's likely
that R would eventually have added a rowsum() function for
compatibility.

  -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland



[Rd] rowsum
Thomas Lumley