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From: Peter Otten <__peter__@web.de>
Subject: Re: Pythonic way to iterate through multidimensional space?
Date: Wed, 06 Aug 2014 14:39:36 +0200
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Xref: csiph.com comp.lang.python:75796

Gayathri J wrote:

> Dear Peter
> 
> Yes the f[t] or f[:,:,:] might give  a marginal increase, 

The speedup compared itertools.product() is significant:

$ python -m timeit -s 'from itertools import product; from numpy.random 
import rand; N = 100; a = rand(N, N, N); r = range(N)' 'for x in product(r, 
repeat=3): a[x] = 0.0'
10 loops, best of 3: 290 msec per loop

$ python -m timeit -s 'from itertools import product; from numpy.random 
import rand; N = 100; a = rand(N, N, N); r = range(N)' 'a[:,:,:] = 0.0'
100 loops, best of 3: 3.58 msec per loop

But normally you'd just make a new array with numpy.zeros().

> but then i need
> to do further operations  using the indices, in which case this wouldnt
> help

Which is expected and also the crux of such micro-benchmarks. They distract 
from big picture.