Support cuDNN v4

[andravin]

Placeholder for cuDNN v4 support development effort.

I am only set up to test on Linux, so it would be helpful if somebody else could test on Windows and Mac.

[kashif]

@andravin happy to look at this issue, is there anything specific you want me to test? thanks!

[andravin]

Hi @kashif I was implementing cuDNN v4 in this fork: https://github.com/andravin/cudnn-python-wrappers

Some things are probably not implemented, been a couple months since I looked at it.

[kashif]

ok thanks @andravin I'll use that and get it working on mac and update it as well...

[andravin]

The first thing to check for each platform is whether the library name specified here is correct:

if sys.platform in ('linux2', 'linux'):
    _libcudnn_libname_list = ['libcudnn.so', 'libcudnn.so.4', 'libcudnn.so.4.0.4']
elif sys.platform == 'darwin':
    # TODO: check darwin version
    _libcudnn_libname_list = ['libcudnn.dylib', 'libcudnn.7.5.dylib']
elif sys.platform == 'win32':
    # TODO: check win32 version
    _libcudnn_libname_list = ['cudnn70_64.dll']
else:
    raise RuntimeError('unsupported platform')

[hannes-brt]

Thanks for contributing @kashif and @andravin. I am currently not using this library myself and therefore also not actively developing it either. If either one of you would like to take stewardship of this project, I'd be more than happy to give you push access to the repo.

[andravin]

I am not actively using it either, but I am happy to help out when I can.

I want to stress that I really only tested the forward path convolution functions with regards to cuDNN support, so really everything else needs a bit of testing. @kashif have you gotten more code coverage in your testing?

[kashif]

@andravin I plan to add more tests and perhaps i will ask you about them when I start. @hannes-brt I would be happy if @andravin takes ownership since that way I can run things by him when I do stuff...

[hannes-brt]

I added both of you as collaborators on the repo.

[kashif]

@hannes-brt thanks!