[issue8644] timedelta.total_seconds needlessly inaccurate, especially for negative timedeltas

[Mark Dickinson]

Mark Dickinson <dickinsm at gmail.com> added the comment:

Perfect!  Applied in r81020.

You're correct that n/10**6 and n/1e6 aren't the same thing, at least for n large enough:

Python 2.7b2+ (trunk:81019:81020, May  9 2010, 10:33:17) 
[GCC 4.2.1 (Apple Inc. build 5659)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from __future__ import division
[35402 refs]
>>> (2**53+1)/10**6
9007199254.740993
[35404 refs]
>>> (2**53+1)/1e6
9007199254.740992
[35404 refs]

In the second case, 2**53+1 first gets converted to a float, and then the division is performed, so there are two points at which a rounding error can be introduced.  The first case only involves one rounding error.

----------
resolution: accepted -> fixed
stage: patch review -> committed/rejected
status: open -> closed

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue8644>
_______________________________________