how to caluclate mutual information for bci data?

I have the bci competition ii dataset iii eeg data.I perform 4 level dwt with 'db2' wavelet.As features i use min,max,std,mean from reconstructed details 2,3 and then i use randomly 50% of the data for classification with linear discriminant analysis (attached script untitled.m).For evaluation of the classification result they propose the mutual infromation (attached script criteria.m). My questions are if i calculate mutual information correctly and if not how can i do it?