% shiftl - shift a column vector up one
%
% shift :: [[N,M]] -> [[N,M]].
%
% Shift array elements back one, padding end with zeros.
% eg [ 1 2 3 4 ] --> [ 2 3 4 0]
function y=shiftl(x)
	if isvector(x)
		y = [ x(2:end); 0];
	else
		y = [ x(:,2:size(x,2)), zeros(size(x,1),1) ];
	end
end
