Re: [R] Loss of numerical precision from conversion to list ?

From: Peter Dalgaard <p.dalgaard_at_biostat.ku.dk>
Date: Fri 21 Jul 2006 - 18:07:31 EST

Duncan Murdoch <murdoch@stats.uwo.ca> writes:

> R tries to use the maximum precision (64 bit mantissa) in the floating
...
> Or perhaps your problem has nothing to do with this; I didn't really
> look at it in detail.

It hasn't. I was off speculating about sum vs rowSums too, but:

> > num.v<- rowSums(((lambda-lambda0)*mu*w.k.sq[,-(K+1)])/(1+lambda*mu))

Inside this, we have mu*w.k.sq[,-(K+1)] . mu is a vector of length 27, and w.k.sq has 10 rows and 28 *columns*. Column-major storage and vector recycling kicks in... If mu has identical elements (never mind the magnitude), of course, the recycling doesn't matter.

-- 
   O__  ---- Peter Dalgaard             ุster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)                  FAX: (+45) 35327907

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Received on Fri Jul 21 18:09:55 2006

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