[R] R on the Zaurus

Stuart Leask stuart.leask at nottingham.ac.uk
Wed Nov 27 17:24:10 CET 2002


(Actually, I believe this little test was suggested by Peter Dalgaard... I
sent Simon the 'correct results' to compare with the Zaurus output...

Stuart Leask)

> Hello All,
>
> I have a working port of R on my SL5500. I've not tested the X windowing
> support yet, but was more concerned about the accuracy of the fp
emulation.
>
> The following is the result of the test which Stuart Leask recommended I
> should try:
>
> Mandrake 8.2
> > x<-NA
> > is.na(x)
> [1] TRUE
> > x+1
> [1] NA
> > 2*x
> [1] NA
>
> Zaurus OZ3
> > x<-NA
> > is.na(x)
> [1] TRUE
> > x+1
> [1] 1
> > 2*x
> [1] 8.29488e-311
>
> Presumably this is the wrong answer. The question is whether it's the
fault
> of the Zaurus' fp emulation, or some sort of incompatibility with the way
R
> is written. Does anyone know for certain which it might be?
>
> If it is a bug in the Zaurus' fp implementation then I don't see any real
> troubles getting it fixed (I'm sure people will be keen to get this
right).
>
> I notice that there are two types of NaNs in the ieee 754 standard, QNaN
> (Quiet NaN) and SNaN (Signalling NaN). Does 8.29488e-311 look familiar (I
> didn't think so)?
>
> Regards,
>
>
> Simon
>
> --------------------------------------------
> Simon Pickering MEng
> Dept. of Mechanical Engineering
> University of Bath
> Bath, BA2 7AY, UK
>
> Tel: +44 (0)1225 383314
> Fax: +44 (0)1225 386928
> --------------------------------------------
>
>
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