[issue1694] floating point number round failures under Linux

Mark Dickinson added the comment: I'm closing this as invalid. -- resolution: -> invalid status: open -> closed __ Tracker <[EMAIL PROTECTED]> __ _

[issue1694] floating point number round failures under Linux

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[issue1694] floating point number round failures under Linux

Tim Peters added the comment: Nice example! Yes, the round() implementation is numerically naive, in this particular case ignoring that x+0.5 isn't necessarily representable (it multiplies the input by 10.0, adds 0.5, takes the floor, then divides by 10.0, and in this specific case adding 0.5 lo

[issue1694] floating point number round failures under Linux

Mark Dickinson added the comment: It's worth noting that Python's round function doesn't quite work as advertised, either: Python 2.6a0 (trunk:59634M, Dec 31 2007, 17:27:56) [GCC 4.0.1 (Apple Computer, Inc. build 5370)] on darwin Type "help", "copyright", "credits" or "license" for more inform

[issue1694] floating point number round failures under Linux

Tim Peters added the comment: Right, Unix-derived C libraries generally do IEEE-754 "round to nearest/even" rounding, while Microsoft's do "add a half and chop" rounding. The Python reference manual says nothing about this, and neither does the C standard (well, C89 doesn't; unsure about C99).

[issue1694] floating point number round failures under Linux

Mark Dickinson added the comment: Is there anything in the Python documentation that implies that '%.1f' % 2.25 should be the string '2.3'? I know that the documentation for the builtin round function implies that round(2.25, 1) should be (the closest representable float to) 2.3, but that's

[issue1694] floating point number round failures under Linux

New submission from Bernhard Mayr: [EMAIL PROTECTED] ~]$ python Python 2.5.1 (r251:54863, Oct 30 2007, 13:54:11) [GCC 4.1.2 20070925 (Red Hat 4.1.2-33)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> f1=0.55 >>> f2=2.25 >>> print '%.1f, %.1f' % (f1, f2) 0.6,