Sorry to post in technical forum, but there's nothing else that seemed appropriate and this is technical to me when choosing between CUDA and OpenCL.

Apparently apple has a patent with 27 claims on OpenCL. And there are only 3 articles I found discussing this. This is an excellent summary of my concerns expressed by somebody else:

I don't understand the answer. Maybe somebody from Khronos can elaborate? The bottom line is, will it ever the a possibility that I have to pay royalties to run OpenCL code I write and sell?