% Compute the covariance coefficient between the spike trains
% p1 and p2 by taking the integral of the crosscorrelation function
% over a window of radius tau and correcting.
% Multiply this number by tau to get the covariance of the
% spike count over an interval of size tau.
% c=cov_coeff(p1,p2,tau,dt)
% dt is the binsize
% NOTE: p1 and p2 should be the same length


function c=cov_coeff(p1,p2,tau,dt)

% T is the length of p1 in the correct units
n=numel(p1);
T=n*dt;

% Define the correction term 'function'
correctionterm=1-abs((-tau:dt:tau))/tau;

% Calculate the correlation function
[cc12,x]=cross_corr(p1,p2,tau,dt);

% Integrate the correlation function
% multiplying by the correctino term
c=sum(correctionterm.*cc12)*dt;