sum accuracy

Wed Apr 13 13:03:06 EDT 2016

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.
"""