Using PPM (Prediction with partial match) for predicting next symbol in sequence.

I'm trying to under the use of the PPM (Prediction with partial match) algorithm to predict the next symbol in a sequence of symbols (e.g. abababa, and the next is likely "b").

I'm experimenting with the follow code from file exchange, but I have no idea how to interpret the output toward getting the next most likely value. the author seems to be unresponsive. Any help would be greatly appreciated. thank you for your time.

http://www.mathworks.com/matlabcentral/fileexchange/18985-prediction-with-partial-match-ppm

[Alex Hamilton]

Did you ever manage to understand this, I would greatly appreciate it if you did and were willing to share