Complex arithmetic in Fortran

[Thomas Koenig]

Am 13.11.24 um 15:55 schrieb Toon Moene:
> 
> Since the Fortran 95 Standard it does (in the current Standard: 7.4.3.2 
> Real type):
> 
> The real type includes a zero value. Processors that distinguish between 
> positive and negative zeros shall treat them as mathematically equivalent
> • in all intrinsic relational operations, and
> • as actual arguments to intrinsic procedures other than those for which
>    it is explicitly specified that negative zero is distinguished.
> 
> [Note that "processor" in Fortran standardese means everything 
> (combined) from the compiler down to the actual hardware].
> 
> So we have to comb through the Standard to see where bullet 2 applies ...

I looked through the current standard, and the only mention of positive
and negative zero I could find were in the IEEE intrinsics.

So, I think we could ignore signed zeros (from the Fortran standard
perspective)

- for complex arithmetic, always
- for real arithmetic, if none of the IEEE modules is USEd

Best regards

	Thomas