The paper can be found in http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6560364 and the matlab code can be downloaded from http://www.openpr.org.cn/index.php/104-How-to-Estimate-the-Regularization-Pa... . Whenever you need to use LDA (linear discriminant analysis), you can also try our method. This method is parameter-free, avoiding the pain of tuning parameters. When applied to large scale data, it is faster than LDA. Despite that the paper is a little mathematical intensive, the matlab code is very easy to use. If you want to use it, there is no need to know the details of all formulas in this paper. Have funJ -- -------------------------------------------------------------------------- ----------------- Associate Professor Jie Gui (Chinese name: 桂杰), PhD Institute of Intelligent Machines, Chinese Academy of Sciences (CAS) Hefei 230031, China Homepage: http://www.escience.cn/people/guijie/index.html --------------------------------------------------------------------------- -----------------