http://my.oschina.net/oncereply/blog?catalog=41825
http://my.oschina.net/oncereply/blog/260755
http://www.ibm.com/developerworks/cn/linux/l-cn-python-optim/
http://blog.sina.com.cn/s/blog_9f48885501018ex8.html
http://ciniao.me/article.php?id=17
http://blog.csdn.net/liangliyin/article/details/5980505
http://www.oschina.net/question/129540_61768