@QuantScientist @mratsim Thanks for your reply~
I am using GeForce GTX 1080, and pytorch can be installed successfully without CUDNN.
I modified tools/setup_helpers/cudnn.py to print environment path of cudnn, and got None.
print 'CUDNN_INCLUDE_DIR is', os.getenv('CUDNN_INCLUDE_DIR')
print 'CUDNN_LIB_DIR is', os.getenv('CUDNN_LIB_DIR')
exit()

CUDNN_INCLUDE_DIR is None
CUDNN_LIB_DIR is None

However, these two path can be got in raw python cmd correctly. So strange. I do not know why they are invalid in pytorch install script.

Selection_001.png815×634 113 KB

I am not familiar with the python package installation, could you please give some help? Many thanks~~