function [out]=fil(in,f);
%
% Filters the data using a first order filter
%
% [out]=fil(in,f);
%
% f is a vector containing the filter constants
%
% Updated to use MATLAB's built in filter routine
%

[D L]=size(in);
for i = 1:L
	x1=in(1,i);
	in(:,i)=in(:,i)-x1;

	out(:,i)=filter([1-f(i)],[1 -f(i)],in(:,i));
	out(:,i)=out(:,i)+x1;
end