Re: (Mis)use of the is_nan_or_na() mapper function

[David Bateman]

The function is_nan_or_na is a mapper function that directly calls
lo_ieee_is_NaN_or_NA. So if there is a problem its almost certainly
in the underlying library function.

For what it is worth I get 

octave:1> p = 1:10; p(3) = NaN; p(5) = NA;
octave:2> isna(p) | isnan(p) 
ans =

  0  0  1  0  1  0  0  0  0  0

octave:3> is_nan_or_na(p)
ans =

  0  0  1  0  1  0  0  0  0  0

So it defintely seems that lo_ieee_is_NaN_or_NA is broken on your
platform.. I suggest you report exact what platform you are running
on including compiler versions, etc and perhaps a workaround can be
included in lo-ieee.h within octave itself...

Regards
David




According to Paul Laub <address@hidden> (on 10/11/04):
> Dear all, 
> 
> Am I missing something or is there a problem with the function 
> is_nan_or_na? I am interested in using it to identify missing 
> data elements (variously marked NaN or NA -- I know, NA is 
> preferable). 
> 
> It appears that is_nan_or_na() does not detect NAs as this
> transcript shows. I am using Octave 2.1.42 in Windows 2000. 
> 
>     184 >> which is_nan_or_na
>     is_nan_or_na is a built-in mapper function 
>     185 >> p = 1:10;
>     186 >> p(3) = NaN;
>     187 >> p(5) = NA;
>     188 >> isna(p) | isnan(p)
>     ans =
> 
>       0  0  1  0  1  0  0  0  0  0     # what I expect
> 
>     189 >> is_nan_or_na(p)
>     ans =
> 
>       0  0  1  0  0  0  0  0  0  0     # not what I expect
> 
>     190 >> is_nan_or_na(NaN)
>     ans = 1
>     191 >> is_nan_or_na(NA)            # well ... 
>     ans = 0
> 
> The workaround is obvious; it is command 188 above. But what gives
> with is_nan_or_na()? 
> 
> Paul Laub 
> 
> P.S. A web search turned up this 2002 discussion issues. 
> 
>     http://www.octave.org/mailing-lists/help-octave/2002/581
> 
> What caught my eye is that in that exchange the function is 
> named with different case, ie., is_NaN_or_NA. I know that
> Octave is case-sensitive. 
> 
> P.P.S. Having NA is a good idea but how is it implemented?
> How do you keep it separate from NaN and Inf and still use 
> IEEE style floating point math? I notice that sprintf("%f", NA)
> returns "NaN".
> 
> 
> 
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