Well it was a weekend project, so I am not sure it is exactly... elegant. But thank you, I accept the compliment :-)

As for my negative conclusions... I wouldn't describe them as "negative", just "objective". Some algorithms are easily adapted to CUDA, and you get an easy win of 10-40x. Others need a lot more work to offer speed gains, and finally, there are some that are simply hopeless (you have to redesign them from scratch).