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Re: Pythonic way to iterate through multidimensional space?

From Peter Otten <__peter__@web.de>
Subject Re: Pythonic way to iterate through multidimensional space?
Date 2014-08-06 14:39 +0200
Organization None
References <lrrdfc$7q7$1@dont-email.me> <53E1E180.6070308@gmail.com> <CAKiaUYz40HJ9bGpv8BpmE7ptK5gzMJJkS0c9BsBXsGiZWbZifg@mail.gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.12699.1407328796.18130.python-list@python.org> (permalink)

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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.

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Thread

Pythonic way to iterate through multidimensional space? Frank Miles <fpm@u.washington.edu> - 2014-08-05 20:06 +0000
  Re: Pythonic way to iterate through multidimensional space? Peter Otten <__peter__@web.de> - 2014-08-05 22:48 +0200
  Re: Pythonic way to iterate through multidimensional space? Frank Miles <fpm@u.washington.edu> - 2014-08-05 20:57 +0000
    Re: Pythonic way to iterate through multidimensional space? Gayathri J <usethisid2014@gmail.com> - 2014-08-06 11:04 +0530
    Re: Pythonic way to iterate through multidimensional space? Chris Angelico <rosuav@gmail.com> - 2014-08-06 16:25 +1000
    Re: Pythonic way to iterate through multidimensional space? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-06 08:33 +0100
    Re: Pythonic way to iterate through multidimensional space? Peter Otten <__peter__@web.de> - 2014-08-06 09:39 +0200
    Re: Pythonic way to iterate through multidimensional space? Tim Chase <python.list@tim.thechases.com> - 2014-08-06 06:39 -0500
  Re: Pythonic way to iterate through multidimensional space? Wojciech Giel <wojtekgiel@gmail.com> - 2014-08-06 09:04 +0100
  Re: Pythonic way to iterate through multidimensional space? Gayathri J <usethisid2014@gmail.com> - 2014-08-06 17:43 +0530
  Re: Pythonic way to iterate through multidimensional space? Peter Otten <__peter__@web.de> - 2014-08-06 14:39 +0200
  Re: Pythonic way to iterate through multidimensional space? Gayathri J <usethisid2014@gmail.com> - 2014-08-06 18:57 +0530

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