[SoC] Week 10 OpenCL Integration

Seth Price seth at pricepages.org
Tue Aug 3 04:01:39 EDT 2010

1) What did I do last week?
All my work can be seen here:

I put a bunch more effort into finding and fixing bugs. The latest bug  
(which I spent way too much time on) seems to be caused by error  
introduced in the GPU. I think I've set up the code to avoid it in the  

I've implemented vectorization, and it runs much faster on both the  
GPU and CPU. You can expect a speedup over the original code from 2x  
using bilinear resampling to 40x using lanczos resampling. This is  
affected by how much manipulation and masks are used by GDAL's  
processing, of course.

What took most of my time this week was implementing a reduced X/Y  
translation matrix. Now the projection numbers are slightly  
interpolated with a greatly reduced GPU memory footprint (16x smaller  
for this matrix).

2) What I plan to do this week.
I think I'm pretty close to being done with OpenCL GDAL. The only  
thing that needs doing is a clean config script to handle compiling.  
There needs to be changes made for it to run on Windows, but I don't  
have a machine to test, so someone else will have to look at that.

Therefore I'll head over to r.sun and see if I can finish that up.

3) Do I have any problems or obstacles which will interfere with my  
We need to finalize what's going on with pj_do_proj() in r.sun, but it  
sounds like this is pretty much done. My family has a hiking trip the  
7th thu the 10th, so I'll either send my next report a few days early  
or late.


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