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
