🚀 go-pugleaf

Gary Houston <ghouston@stats.govt.nz> writes:

>On further reflection I have realized that my missing value 
>problem was not well specified. Assuming the use of the
>IEEE 754-1985 standard, it is relatively easy to 
>make a missing value in C and pass it back to S using the
>NAOK=T option: any of NaN values in C (i.e., any number starting
>with 0x7FF) will be converted by S to NA. Therefore, the
>1/a - 1/a trick works.

Note : The result of passing an NaN from C back to S is again an NaN;
it is not "converted by S to NA". The S functions is.na() and is.nan()
will both return T for values created from IEEE undefined arithmetic
operations.

Rod Ball			email : rod@marcam.dsir.govt.nz
DSIR Applied Maths		phone : 64-9-893-660 Ext. 6709
P.B. Auckland			fax   : 64-9-863-330
New Zealand
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