Remove CUDA 9, Re install CUDA 8

CUDA 9 just released, tensorflow 1.3 has not support CUDA9 yet. 

download  CUDA 8.0 at https://developer.nvidia.com/cuda-80-ga2-download-archive.  or click "Legacy Release" on the bottom of page.

Step 1: remove previous CUDA : $ sudo apt autoremove cuda   

Step 2: install CUDA  by following instruction : $sudo dpkg -i cuda-repo-ubuntu1604-8-0-local-ga2_8.0.61-1_amd64.deb

Step3 :  $sudo apt-get install cuda-8-0. 

after installation, 

Step 1: install TensorFlow (https://www.tensorflow.org/install/install_linux#the_url_of_the_tensorflow_python_package). Ensure your TensorFlow is python 2 (by using pip 2)or python 3(pip or pip3). 

Step  2: import TensorFlow.  Now you will see a "import error: libcudnn.so.6" . Now you need to install CUDNN from here (https://developer.nvidia.com/rdp/cudnn-download) . 

credit to "http://www.cnblogs.com/xuliangxing/p/7575586.html". Check it for detail.

1 #解压文件 2 tar -zxvf cudnn-8.0-linux-x64-v7.tgz 3  4 #切换到刚刚解压出来的文件夹路径 5 cd cuda  6 #复制include里的头文件（记得转到include文件里执行下面命令） 7 sudo cp /include/cudnn.h  /usr/local/cuda/include/ 8  9 #复制lib64下的lib文件到cuda安装路径下的lib64（记得转到lib64文件里执行下面命令）10 sudo cp lib*  /usr/local/cuda/lib64/11 12 #设置权限13 sudo chmod a+r /usr/local/cuda/include/cudnn.h 14 sudo chmod a+r /usr/local/cuda/lib64/libcudnn*15 16 #======更新软连接======17 cd /usr/local/cuda/lib64/ 18 sudo rm -rf libcudnn.so libcudnn.so.7   #删除原有动态文件，版本号注意变化，可在cudnn的lib64文件夹中查看   19 sudo ln -s libcudnn.so.7.0.2 libcudnn.so.7  #生成软衔接（注意这里要和自己下载的cudnn版本对应，可以在/usr/local/cuda/lib64下查看自己libcudnn的版本）20 sudo ln -s libcudnn.so.7 libcudnn.so #生成软链接21 sudo ldconfig -v #立刻生效

Beware the correct CUDA version and cudnn version.  if you have the matched version of libcudnn.so.X after installed cudnn, no soft link need. 

Summary :

1. Install CUDA 8  by $sudo apt-get install cuda-8-0.  or the install file automatically intall CUDA 9

2. Install cudnn X. for libcudnn.so.X file missing .

3. Check the version if matched .

4.  add path environment commands :

export PATH=/usr/local/cuda-8.0/bin:$PATH 

export LD_LIBRARY_PATH=/usr/local/cuda-8.0/lib64:$LD_LIBRARY_PATH

export CUDA_HOME=/usr/local/cuda

It very useful when you want to switch different CUDA version.  

Useful commands: 

sudo apt-get --purge remove cuda
sudo apt autoremove
to remove cuda 9.0

sudo apt-get clean
to clear apt-cache

sudo dpkg -i cuda-repo-ubuntu1604-8-0-local-ga2_8.0.61-1_amd64.deb
sudo apt-get update
sudo apt-get install cuda-8-0