[Insight-users] Speed

[Gaëtan Lehmann]

Le 9 févr. 11 à 11:47, Dan Mueller a écrit :

> Did you compile in Release mode?
>
> On 9 February 2011 10:33, Gib Bogle <g.bogle at auckland.ac.nz> wrote:
>> I have encountered something that surprises me, and I'd like to  
>> hear any
>> comments.  I'm not being critical, it's just interesting.  I was  
>> using
>> MeanImageFilter, and was surprised at how slowly it ran on my  
>> image.  Since
>> the filter function is very simple, I decided to code up my own  
>> version, to
>> see if I could get it done faster.  I'm not really a competent C++
>> programmer, so I've just implemented an efficient algorithm in C.
>>
>> I'm testing with a greyscale image 955x963x100, on a Core i7 W7  
>> machine (4
>> cores, 8 threads).  Setting each filter radius to 5, the  
>> MeanImageFilter
>> processing takes 1184 sec, using all 8 threads (100% CPU usage).   
>> My own
>> averaging code takes 105 sec, using only a single thread (12.5% CPU  
>> usage).
>>
>> Why the big difference?

Hi,

As suggested by Dan, building in Release mode can make a huge  
difference.

But implementing an efficient algorithm, as you did, can also explain  
that difference.
Have you tried a more efficient implementation like the  
BoxMeanImageFilter? IIRC, it is running a lot faster.

Regards,

Gaëtan

-- 
Gaëtan Lehmann
Biologie du Développement et de la Reproduction
INRA de Jouy-en-Josas (France)
tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
http://voxel.jouy.inra.fr  http://www.itk.org
http://www.mandriva.org  http://www.bepo.fr

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