Permutation entropy

% Calculate the permutation entropy

% Input: y: time series;
% m: order of permuation entropy
% t: delay time of permuation entropy,

% Output:
% pe: permuation entropy
% hist: the histogram for the order distribution

%Ref: G Ouyang, J Li, X Liu, X Li, Dynamic Characteristics of Absence EEG Recordings with Multiscale Permutation %

% Entropy Analysis, Epilepsy Research, doi: 10.1016/j.eplepsyres.2012.11.003
% X Li, G Ouyang, D Richards, Predictability analysis of absence seizures with permutation entropy, Epilepsy %

% Research, Vol. 77pp. 70-74, 2007