function [p,t]=acorr(y,rmax);% function [p,t]=acorr(y,r);%% Calculates an approximation to the autocorrelation function for a timeseries% y.%%Michael Small%3/3/2005%ensmall@polyu.edu.hkif nargin<2,  rmax=length(y);end;X=mean(y);N=length(y);wait=waitbar(0,'acorr : working...');for r=0:rmax  waitbar(r/rmax,wait);	p(rmax+1+r)=1/(N)*dot(y(1:N-r)-X,y(r+1:N)-X);	p(rmax+1-r)=p(rmax+1+r);end;p=p/(p(rmax+1));t=-rmax:1:rmax;close(wait);