Re: ATAN inconsistencies

[Michael Werger <mwerger(at)astro.estec.esa.nl>]

"Kenneth P. Bowman" wrote:
> 
> Here's a platform dependency that took me quite a while to track down.
> 
> The SGI (IRIX) version of IDL returns 0.0 when you try to take the
> arctan(0/0).  The Alpha version (properly) returns a NaN.
> 
> Ken Bowman
> 
> IDL Version 5.1 (IRIX mipseb). Research Systems, Inc.
> IDL> print, atan(0.0, 0.0)
>       0.00000
> 
> IDL Version 5.1 (OSF alpha). Research Systems, Inc.
> IDL> print, atan(0.0, 0.0)
>          NaNQ
> % Program caused arithmetic error: Floating illegal operand

IDL 5.2 on Solaris 2.7:

IDL> print, atan(0.0, 0.0)
      0.00000
... Any comments about the proper handling? ;-) 

-- 
Michael Werger                                        ------------o
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