function y = ad_pattern(x,  wsize, range)
% y=ad_pattern(x,wsize,maxlag) -  Pattern of neural coincidence
% x: spike train, 
% wsize: coincidence window size, range: histogram size, in samples

global sr;

% exponential window of duration 4*wsize.  
% n = 4 * wsize * sr;
% z = 1:n;
% w = exp(- (z-1) * 4 / n);

% square window of duration wsize.
n = round(wsize);
w = ones(1, n);

% convert time list to count array
N = round(max(x) .* sr);
a = histogram(x, N);
%a = hist(x, N);

% convolve with window
mask = conv(a, w);

% clip mask at 1
mask = 1- mask;
mask = 1 - (abs(mask) + mask) ./ 2;


% cross correlation
y = zeros(1, range);
for i = 1:range
	z = (1-mask(:,i:N)) .* a(:, 1:N-i+1);
	y(i) = sum(z);
end