现在重新在Ubuntu 12.04下配置NVIDIA CUDA5.5，特此记录参考网站以便查阅。
环境：Ubuntu 12.04+Cuda5.5
1. 判断安装环境：
The setup of CUDA development tools on a system running the appropriate version of Linux consists of a few simple steps:
Verify the system has a CUDA-capable GPU.
Verify the system has a supported version of Linux.
Verify the system has gcc installed.
见官方配置手册：http://docs.nvidia.com/cuda/cuda-getting-started-guide-for-linux/index.html
2. 下载镜像：
https://developer.nvidia.com/cuda-downloads
下run好了
3. 安装必要的库
sudo apt-get install freeglut3-dev build-essential libx11-dev libxmu-dev
libxi-dev libgl1-mesa-glx libglu1-mesa libglu1-mesa-dev
4. 删除已有nvidia，拉黑名单
sudo apt-get remove --purge nvidia*
sudo nano /etc/modprobe.d/blacklist.conf
blacklist.conf加入
lacklist amd76x_edac
blacklist vga16fb
blacklist nouveau
blacklist rivafb
blacklist nvidiafb
blacklist rivatv
5. Ctrl+Alt+F1, 登陆后安装
sudo service lightdm stop
chmod +x cuda_5.5.22_linux_64.run
sudo ./cuda_5.5.22_linux_64.run
Cuda5.5集成了toolkit，sdk和driver, 所以安装的时候一路同意下来就好了
6. 得到以下安装结果
Driver: Installed
Toolkit: Installed In /Usr/Local/Cuda-5.0
Samples: Installation Failed. Missing Required Libraries.
也就是SDK安装失败，这个官方手册上也提到了解决方案。
7. 单独安装SDK
解压sdk：
sh cuda_5.5.22_linux_64.run -extract=/path/to/extract/dir/
到根目录下的/path/to/extract/dir/去找cuda-samples_5.5.22_*******.run, 安装
sh cuda-samples_5.5.22_*******.run
8. Path配置：
$sudo gedit etc/profile或~/.bashrc
export PATH=$PATH:/usr/local/cuda-5.5/bin
export LD_LIBRARY_PATH=/usr/local/cuda-5.5/lib64:/lib
使之生效：
source /etc/profile（对应profile）或sudo ldconfig（对应bashrc）
还有一种装sdk的方法见http://askubuntu.com/questions/338907/how-to-install-cuda-5-5-under-ubuntu-12-04-lts-64-bit
9. 验证
见官网http://docs.nvidia.com/cuda/cuda-getting-started-guide-for-linux/index.html#verify-installation
10. Cuda Hello World:
https://devtalk.nvidia.com/default/topic/486692/cuda-programming-and-performance/guide-installing-cuda-sdk-on-linux-walkthrough-on-how-to-install-the-cuda-sdk-and-build-the-example/
正文最下方
11. 装好theano的前提下配置~/.theanorc配置GPU
sudo vim ~/.theanorc
写入
[global]
floatX = float32
device = gpu
进行测试：http://deeplearning.net/software/theano/tutorial/using_gpu.html#testing-theano-with-gpu
此外附上其他配置参考：
theano+python模块
（Ubuntu 12.04自带python不用装，但要注意系统里很多模块依赖python，没事不要随便删！！！）