[R] R on the Zaurus

Simon Pickering enpsgp at bath.ac.uk
Wed Nov 27 13:58:51 CET 2002

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)?



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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