> The main problem is OpenCL seems an order of magnitude more complex than CUDA. Do you have any experience to back that up with? I've worked with both and I k

> The main problem is OpenCL seems an order of magnitude more complex than CUDA. Do you have any experience to back that up with? I've worked with both and I know that there are areas where your "order of magnitude" (which BTW I'd like to see on paper, quantified) does hold up, e.g. dev tools, but in general your claim is simply false. > To be honest, Cuda seems semi-portable just because (according to documentation and tutorials I've read) you do little more than allocate memory, tag functions, write loops and the compiler figures out the rest. Nonsense, you're likely confusing OpenACC with CUDA, the CUDA runtime API is in many cases considerably more simple than OpenCL, but it requires a compiler, and frankly often times is screams rushed design/implementation. In contrast, the CUDA driver API is quite similar to OpenCL. ...and BTW OpenACC is "open" only on paper and in fact it is a very divisive move that has created conflicts, polarized the community, and undermined collaboration between multiple parties (in particular with the OpenMP proponents). > Also, the latest pdf-pamphlet of the Khronos Group on opencl 1.2 just says they're "exploring" an open source implementation of the spec, which doesn't encourage one to imagine the spec as available. The latest spec is 2.0 FYI; can you explain my how on earth does one's imagination go astray so badly to believe that just because there is no reference implementation one would consider the spec "not available". Don't get me started with the examples of standards that exist without an official reference implementation. > Edit: Researching this, it seems that the CUDA compiler actually has been integrated into clang/llvm. An open spec with open compiler seems as open as one can get with software - it only targets NVidia but you can just complain Linux was proprietary when it originally only targeted Intel. BS. Show me the "open spec of CUDA". Even if one did exist, good luck trying to influence the design of it if you're not an big oil company, Google, Audi or GM. Also, try to use the CUDA name without having to pay a ton of money. And you seem to forget that the "open compiler" does not actually generate byte-code (that's done by the propritary JIT compiler) and even if did, you still nee NVIDIA's proprietary driver to run it.