[GRASS-dev] OpenCL Parallelization

Jeshua Lacock jeshua at OpenOSX.com
Fri Sep 18 00:32:18 EDT 2009

On Sep 15, 2009, at 10:29 PM, Helena Mitasova wrote:

>> Do you think it might be different with the advent of OpenCL?
> it should not be a separate version, it should be one module that  
> optionally takes advantage
> of multiple processors. One thing to try out would be to parallelize  
> the linear equation solver -
> that would benefit not only v.surf.rst but also v.vol.rst and other  
> code that calls it.
> Soeren may have some suggestions (he has just added some solvers to  
> GRASS and I think he
> did some parallel computations as well).

Sounds good. In what file may I find the source for linear equation  

>>> I may have one more recent version that was done for beowulf
>>> cluster. Let me know if you would like to look at it.
>> Please feel free to email me off list.
> here it is - you can see that at this point it is quite obsolete - I  
> am not sure
> that anybody has ever actually used it
> http://skagit.meas.ncsu.edu/~helena/grasswork/grasscontrib/rst/rstmods2fixed.tar.gz
>>> That was done at the segment
>>> level, but running it just with parallelized lineq solver should  
>>> help too because that would allow
>>> larger segments and larger overlaps.
>> I may even have a customer that would help fund development for  
>> v.surf.rst.
> that would be great - we use it a lot with lidar data - millions of  
> points so it would be great help.

My client is an archeologist that takes magnetometer samples in the  
field and also has millions of points (a large site might be up to 10  
million samples).

He said he was definitely interested help paying for this to be  
developed. He mentioned that "Manifold GIS" is already taking  
advantage of OpenCL and said the performance increase was nothing  
short of amazing. He said some very intensive operations are now  
nearly realtime. He is trying to switch entirely over to GRASS for all  
of his GIS work.

I am sure this is a difficult question to answer as it depends on a  
lot of variables, but can anyone offer a ball park estimate of how  
much work might be involved to parallelize the linear equation solver?  
I am just trying to get a feel for how much work might be involved.


Jeshua Lacock, Owner
phone: 208.462.4171

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