[Rd] rowsum

[Thomas Lumley]

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