Test OpenCL

[bkmgit]

• Partially addresses CI tests #90
• Can squash commits.
• The precision tests cause a segmentation fault, probably due to memory requirements. Maybe a small set of test cases can be considered?

[DTolm]

Hello,

Thank you for the effort, I will need to check on how this will work and decide on the small set of tests that can be done in CI (and to automatically decide if accuracy is good) - then it can be done as a separate script file. I think it will be better this way, than just relaunching all precision verification scripts every time.

Best regards,
Dmitrii

[bkmgit]

Thanks for the library. Some of the precision failures may be due to the implementations of OpenCl/Vulkan not just the FFT library. Can add other possible backends, in particular llvmpipe and HIP-CPU that can run on CPU once a subset of tests is chosen. These will also be helpful for packaging the library in Linux distributions.