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Re: sum accuracy

From Peter Otten <__peter__@web.de>
Newsgroups comp.lang.python
Subject Re: sum accuracy
Date 2016-04-13 19:03 +0200
Organization None
Message-ID <mailman.86.1460567115.15650.python-list@python.org> (permalink)
References <570E78F9.8050409@chamonix.reportlab.co.uk> <nelu4b$en2$2@ger.gmane.org>

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Robin Becker wrote:

> Does anyone know if sum does anything special to try and improve accuracy?
> My simple tests seem to show it is exactly equivalent to a for loop
> summation.

If you are worried about accuracy and your values are floating point numbers 
use math.fsum():

"""
fsum(...)
    fsum(iterable)
    
    Return an accurate floating point sum of values in the iterable.
    Assumes IEEE-754 floating point arithmetic.
"""

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Re: sum accuracy Peter Otten <__peter__@web.de> - 2016-04-13 19:03 +0200

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