[issue22590] math.copysign buggy with nan under Windows

2014-10-13 Thread Mark Dickinson
Mark Dickinson added the comment: Antoine: is it okay to close this as wont fix? -- assignee: - mark.dickinson ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22590 ___

[issue22590] math.copysign buggy with nan under Windows

2014-10-13 Thread Antoine Pitrou
Antoine Pitrou added the comment: Yep, it's ok. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22590 ___ ___ Python-bugs-list mailing list

[issue22590] math.copysign buggy with nan under Windows

2014-10-13 Thread Mark Dickinson
Changes by Mark Dickinson dicki...@gmail.com: -- resolution: - wont fix status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22590 ___

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Antoine Pitrou
New submission from Antoine Pitrou: Z:\c:\Python27\python.exe Python 2.7.8 (default, Jun 30 2014, 16:03:49) [MSC v.1500 32 bit (Intel)] on win32 Type help, copyright, credits or license for more information. import math math.copysign(0.0, float(nan)) -0.0 ^Z Z:\c:\Python34\python.exe

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Mark Dickinson
Mark Dickinson added the comment: Why do you consider this a bug? -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22590 ___ ___ Python-bugs-list

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Mark Dickinson
Mark Dickinson added the comment: More info: the reason for the difference is that in Python 3.4, float(nan) and float(inf) create the float directly from the appropriate bit-pattern, rather than deferring to the platform's definition of nan. This change was introduced to avoid obscure

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Antoine Pitrou
Antoine Pitrou added the comment: Ah, apparently it was already reported as issue14521... Well, it's bug in as much as it shows different behaviour across platforms... AFAICT, we try to provide consistent math behaviour despite possible platform variations. --

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Antoine Pitrou
Antoine Pitrou added the comment: Also, the fact that we support float('nan') and float('-nan') as producing different bit patterns means we should perhaps produce the right sign bit for each (it seems that's the problem here). import struct struct.pack(d, float(nan))

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Mark Dickinson
Mark Dickinson added the comment: we should perhaps produce the right sign bit for each Perhaps. But given that signs of NaNs are pretty much meaningless anyway (the IEEE 754 standard explicitly refuses to attach any meaning to NaN sign bits, and the sign bit of a NaN result is not

[issue22590] math.copysign buggy with nan under Windows

2014-10-09 Thread Antoine Pitrou
Antoine Pitrou added the comment: Yes, things are ok under 3.x. We'll probably disable our NaN tests under Windows anyway, since they aren't very useful as you point out. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue22590