[Tutor] Summing arrays

Peter Otten __peter__ at web.de
Thu Mar 16 06:10:11 EDT 2017

Peter Otten wrote:

> (Specifying dtype=float forces floating point arithmetic which is inexact)

I found a way to avoid the error:

>>> import numpy as np
>>> def sum2(N):
...     a = np.arange(1, N+1, dtype=object)
...     return (2*(1+3**(a-1))).sum()
>>> sum2(50)

As this operates on int objects rather than C/machine language numbers this  
will probably be significantly slower than dtype=int or dtype=float.

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