- matlab + windows + CUDA
- octave + linux + CUDA
- octave + linux + Free OpenCL
So you're halfway there and it could be better but it could also be worse.
Writing a very high performance piece of software against a bunch of trade-secret grade hardware for which the manufacturer already provides a bunch of support for many people is not worth the trouble. As long as Nvidia supports their hardware using CUDA and OpenCL is not going to be brought up to that level this will likely continue.
A positive view would seem to me that this midway position will allow more people to move to Octave which in the longer run might free up some funds somewhere to tackle the problem you mention.
The goal is "have software that works," not "have software that retains ideological purity at the cost of advancement."
the issue with free OpenCL implementations on the GPU is that the runtime will be closely coupled with the device driver, so short of open source drivers, there most likely wont be an OpenCL runtime that uses proprietary drivers.
that said, i believe both open source nvidia and radeon drivers support some level of OpenCL, although it's been a while since i've checked them..
nvidia will do what nvidia will do, they obviously have quite a lot of upstream swimming to do before they realise that CUDA is not the best approach to take.
Octave is a GNU package. GNU's purpose is to ensure that you can use free software. Running to tie Octave to flashy features like GPU acceleration without first pausing to fix the initial problem of non-free GPU acceleration is putting the horse before the cart. This works against Octave's goal, to provide a free alternative to Matlab, one that lets you understand and control your computations down to the hardware level. If we don't emphasise software freedom, then there is no need for Octave, since we already have Matlab. Indeed, it is this very freedom that nvidia is abusing here to accelerate Octave's BLAS libraries, a task that would be much more difficult with Matlab, where they don't have the source code.
I know that nobody wants to even think that this problem exists and even fewer people want to fix Clover because it's such a difficult task, but it's a task that we can't ignore.
Note also that because the GPU libraries are not a system library as defined by the GPL (they are not shipped with the OS), you can't even distribute GPU-accelerated Octave object code. We consider the Octave C++ API to fall well under the domain of the GPL's copyleft.
Personally, as a GNU Octave developer, I am very unhappy that nvidia is using Octave to advertise its hardware and non-free drivers. I am also unhappy that nvidia is luring users to use non-free software, acting against our goals. I reiterate Linus Torvalds's well-known sentiments against nvidia.