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From: Helmut Jarausch <jarausch@igpm.rwth-aachen.de>
Newsgroups: comp.lang.python
Subject: Re: How to make this faster
Date: 5 Jul 2013 10:07:57 GMT
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On Fri, 05 Jul 2013 10:38:35 +0100, Fábio Santos wrote:

> [Skipping to bottleneck]
> 
>> def find_good_cell() :
> 
> In this function you are accessing global variables a lot of times. Since
> accessing globals takes much more time than accessing locals, I advise you
> to assign them to local names, and use them.

I've tried to use local "references" like
G= Grid and using G instead of Grid below and similarly for
Row_Digits, Col_Digits and Sqr_Digits but it had no noticeable effect.

> 
>>   Best= None
>>   minPoss= 10
>>   for r in range(9) :
>>     for c in range(9) :
>>       if  Grid[r,c] > 0 : continue
>>       Sq_No= (r//3)*3+c//3
>>       Possibilities= 0
>>       for d in range(1,10) :
> 
> On this condition (below) you can try to check which condition is True more
> often and put that condition first in order to take advantage of short
> circuiting and minimize array access.
Unfortunately, that's unpredictable.
> 
>>         if Row_Digits[r,d] or Col_Digits[c,d] or Sqr_Digits[Sq_No,d] :
> continue

Many thanks,
Helmut