http://deeplearning.stanford.edu/wiki/index.php/Exercise:PCA_in_2D，斯坦福深度学习教程的代码-http://deeplearning.stanford.edu/wiki/index.php/Exercise:PCA_in_2D, Stanford depth tutorial code

http://deeplearning.stanford.edu/wiki/index.php/Exercise:PCA_and_Whitening斯坦福的深度学习的教程的练习，是关于数据预处理的-http://deeplearning.stanford.edu/wiki/index.php/Exercise:PCA_and_Whitening Stanford deep learning tutorial exercises about data preprocessing

斯坦福大学深度学习，PCA主成分分析的补充完的代码-PCA principal component analysis of deep learning at Stanford, added the code

基于PCA和白化的数据预处理操作，PCA具有两个功能：维数约减和数据可视化；白化的目的是去掉数据之间的相关性。深度学习的一个主要工作就是数据的预处理-Based on PCA and data pre-whitening operation, PCA has two functions: dimensionality reduction and data visualization whitening purpose is to remove the correlation between t