3D array problem in Python (Happyman)

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3D array problem in Python (Happyman)

federico vaggi-2
There are faster ways to loop over the array using array slicing:


If, however, you have to apply a slow function to all non-zero elements, that will probably be your bottleneck, and fast access using array slicing won't help you.

By the way, as a quick hint, an easy way to access all non-zero elements of an array is using logical indexing, which you will be familiar with if you've used MATLAB before.  You appear however to be using python lists and not numpy arrays judging by your syntax.
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Message: 1
Date: Sun, 30 Dec 2012 07:32:13 +0400
From: Happyman <[hidden email]>
Subject: [SciPy-User] 3D array problem in Python
To: scipy-user <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain; charset="utf-8"

 Hello

I have 3 dimensional array ?which I want ?to calculate in a huge process. Everything is working well if I use ordinary way which is unsuitable in Python like the following:

nums=32
rows=120
cols=150

for k in range(0,nums):
? ? ? ? ? for i in range(0,rows):
? ? ? ? ? ? ? ? ? ? ?for j in range(0,cols):
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? if float ( R[ k ] [ i ] [ j ] ) == 0.0:
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?val11 [ i ] =0.0
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? else:
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?val11[ i ] [ j ], val22[ i ][ j ] = integrate.quad( lambda x : ?F1(x)*F2(x) , 0 , pi)

But, this calculation takes so long time, let's say about ?1 hour (theoretically)... Is there any better way to easily and fast calculate the process such as [ F( i ) for i in xlist ] or something like that rather than using for loop?


?
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