[Numpy-discussion] Slow conversion from list to arrays

Nadav Horesh nadavh at visionsense.com
Wed Dec 31 03:07:02 CST 2003


It works excellent. I see also that there is a corresponding update in the CVS.

  Happy new (and peaceful) year,
   Nadav.


-----Original Message-----
From:	Todd Miller [mailto:jmiller at stsci.edu]
Sent:	Tue 30-Dec-03 16:34
To:	Nadav Horesh
Cc:	numpy-discussion
Subject:	Re: [Numpy-discussion] Slow conversion from list to arrays
On Thu, 2003-12-25 at 03:27, Nadav Horesh wrote: 
> The conversion for a list of large arrays into a matrix is very slow in
> numarray while reasonably fast:
> 
> >>> from numarray import *
> >>> a = [arange(200000), arange(200000), arange(200000), arange(200000)]
> >>> aa = array(a)   # Very slow
> 
> --------------------------------
> 
> >>> from Numeric import *
> >>> a = [arange(200000), arange(200000), arange(200000), arange(200000)]
> >>> aa = array(a)   # Fast
> 
> Python version:    2.3.3
> numarray version:  Official 0.8
> 
> Tested under WinXP and RH9 linux.
> 
> Any workaround?
> 
Try concatenate.  For the array sizes you're looking at,  numarray does
OK.  You may have to adjust the result shape.

Todd 

>   Nadav
> 
> 
> 
> 
> 
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Todd Miller 			
Space Telescope Science Institute
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