[R] Re: precision, incorrect(?) tapply() NA's

[Peter Dalgaard BSA]

David James <dj at research.bell-labs.com> writes:

> > [1] 0.000000e+00 0.000000e+00 0.000000e+00 1.110223e-16 6.441705e-01
> > [6] 4.679352e-01 1.584967e+00 1.162720e+00
> 
> which agrees with unique(r)
> 
> > unique(r)
> > [1] 0.6931472 0.6931472 1.3373177 1.8052529 3.3902202 4.5529401
> 
> (note that .Machine$double.eps is [1] 2.220446e-16, twice the 4th diff.)

Yep, but since the number is < 1 and double.eps is a relative
quantity, it's probably still a last-bit representation issue in 64
bit doubles (i.e. it is not the infamous Intel extended precision
playing tricks on us again.)

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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