Some suggested algorithms to add  #54

From Mallet: https://github.com/mimno/Mallet/tree/master/src/cc/mallet/classify

• Maximum Entropy classifier: https://github.com/mimno/Mallet/blob/master/src/cc/mallet/classify/MCMaxEnt.java
• Rank Maximum Entropy classifier : https://github.com/mimno/Mallet/blob/master/src/cc/mallet/classify/RankMaxEnt.java
• Posterior Regularization:
  https://github.com/mimno/Mallet/blob/master/src/cc/mallet/classify/MaxEntPRTrainer.java
• Decision Tree
• Balanced Winnow: https://github.com/mimno/Mallet/blob/master/src/cc/mallet/classify/DecisionTree.java