@richard
under /usr/local/cuda/lib64 I do have libcudnn.so.5 and libcudnn.so.6.
Then I type cat /usr/local/cuda/include/cudnn.h | grep CUDNN_MAJOR -A 2 in shell, and it did print out my current cudnn version is 6021.
Moreover, I remove export LD_LIBRARY_PATH=/usr/local/cuda-8.0/lib64\${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}} from .bashrc, and replace it with export LD_LIBRARY_PATH=/home/adnan/ML_packages/cudnn6/cuda/lib64. Not working.