New submission from Jean-Michel Fauth <[email protected]>:
I did not find any report about this.
Windows 7, Python 2.6.4
>>> float('inf') == float('inf')
True
>>> float('-inf') == float('-inf')
True
>>> float('-inf') == float('inf')
False
>>> float('-inf') != float('inf')
True
>>> float('nan') == float('nan')
False
>>> float('nan') != float('nan')
True
>>>
I'm not an expert on that field, I wonder if the following is
not related to a sign bit missmatch, see also Python 3.1.1 below.
>>> copysign(1, float('inf'))
1.0
>>> copysign(1, float('-inf'))
-1.0
>>> copysign(1, float('nan'))
-1.0
>>> copysign(1, float('-nan'))
-1.0
>>>
Windows 7, Python 3.1.1
>>> float('inf') == float('inf')
True
>>> float('-inf') == float('-inf')
True
>>> float('-inf') == float('inf')
False
>>> float('-inf') != float('inf')
True
>>> float('nan') == float('nan')
False
>>> float('nan') != float('nan')
True
>>>
Same behaviour as with Python 2.6.4
>>> copysign(1, float('inf'))
1.0
>>> copysign(1, float('-inf'))
-1.0
>>> copysign(1, float('nan'))
-1.0
>>> copysign(1, float('-nan')) <<<<<<<<<<<<<<<<<<<
1.0
>>>
Different behaviour from Python 2.6.4
----------
components: None
messages: 97432
nosy: jmfauth
severity: normal
status: open
title: Two float('nan') are not equal
type: behavior
versions: Python 2.6
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Python tracker <[email protected]>
<http://bugs.python.org/issue7660>
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