cuDNN library is provided as a shared library file and can be downloaded from NVIDA website, but you must be registered as a CUDA developer.
After download, you need to let the Torch binding know where the library is located by either temporarily setting LD_LIBRARY_PATH or moving the libcudnn* into trusted directory.
# download cudnn-6.5-linux-armv7-R1.tgz
tar xvf cudnn-6.5-linux-armv7-R1.tgzTo link the library:
mv cudnn-6.5-linux-armv7-R1/lib* /usr/local/lib/
sudo ldconfigNow, luarocks install cudnn will install Torch bindings (written by Soumith, https://github.com/soumith/cudnn.torch) for cuDNN library.