[gdal-dev] Availability of Lanczos and cubicspline in gdaladdo

[Adam Nowacki]

Seth Price wrote:
> I actually hope to be addressing performance in my GSoC project. I'm
> interested in rewriting the GDAL resampling code to CUDA, so the graphics
> card does the hard work. For example, instead of processing one pixel at a
> time, the latest GeForce GTX 260 would be able to process 216. I'm hoping
> for CUDA to be 50 to 100 times faster.
> 
> Make sure you're using GDAL 1.6 or later, I recently rewrote the regular
> Lanczos/cubicspline warping code to be much faster.
> ~Seth

You can achieve pretty amazing speeds on the CPU alone. I have a SSE3 
(would be trivial to rewrite as plain old SSE, probably a bit slower) 
Lanczos sampler with 4x4 kernel that runs at ~70 000 000 samples per 
second with float data type on a 2.33GHz Intel Xeon E5410 (one thread). 
I was considering porting the sampler to GDAL but found that I would 
have to rewrite the whole warping code to get any useful speed boost, 
including heavily optimizing coordinate transformations.