切换cuda版本
修改~/.bashrc文件，加入以下代码：
export PATH="$PATH:/usr/local/cuda-8.0/bin"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/local/cuda-8.0/lib64/"
export LIBRARY_PATH="$LIBRARY_PATH:/usr/local/cuda-8.0/lib64" 查看cuda版本
$ nvcc --version
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2017 NVIDIA Corporation
Built on Fri_Sep__1_21:08:03_CDT_2017
Cuda compilation tools, release 9.0, V9.0.176创建软连接
sudo rm -rf /usr/local/cuda #删除之前创建的软链接
sudo ln -s /usr/local/cuda-8.0 /usr/local/cuda #创建新 cuda 的软链接