function [result]=sim_uncert(data,bins)
% function [result]=sim_uncert(data,bins)
% evaluate the simmetrical uncertainty
% of the bivariate dataset data by using 
% the number of bins specified by bins

% Copyright (c) 2004-2006 Alessio Botta, Alberto Dainotti, Antonio Pescapè
% Email: {a.botta , alberto , pescape }@unina.it
% DIS - Dipartimento di Informatica e Sistemistica 
% University of Napoli Federico II, ITALY
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base=2;                         %defines the base of the log for the entropy
n1 = hist3(data,[bins bins]);   %calculates the 3d histogram of the dataset
Pxy=n1./sum(sum(n1));           %calculates the joit probability mass function (pmf)
Px=sum(n1)/sum(sum(n1));        %calculates the marginal pmf of the rows of the dataset
Py=sum(n1')/sum(sum(n1'));      %calculates the marginal pmf of the columns of the dataset
mi=mutual_info(Px,Py,Pxy,base);     %calculates the mutual information of the two random variables

result=2*mutual_info(Px,Py,Pxy,2)/(entropy_base(Px,base)+entropy_base(Py,base)); %calculates the final result