[R] rowSums() and is.integer()

[Prof Brian Ripley]

On Tue, 20 Nov 2007, Tim Hesterberg wrote:

> I wrote the original rowSums (in S-PLUS).
> There, rowSums() does not coerce integer to double.

Actaully, neither does R.  It computes a double answer but does no 
coercion per se.

> However, one advantage of coercion is to avoid integer overflow.

Indeed, as I told Robin Hankin privately, that was the design reason.

>
> Tim Hesterberg
>
>> ...  So, why does rowSums() coerce to double (behaviour
>> that is undesirable for me)?
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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