samer@32: function Z=smooth_with(h,i,Y)
samer@32: % smooth_with - Smooth a signal by convolution without changing length
samer@32: %
samer@32: % smooth_with :: [[M]], 1..M, [[N]] -> [[N]].
samer@32: 
samer@32: m=length(h);
samer@32: h=stoch(h(:))';
samer@32: csh=cumsum(h);
samer@32: rsh=fliplr(cumsum(fliplr(h)));
samer@32: 
samer@32: if isvector(Y), Z=sm(Y);
samer@32: else Z=maprows(@sm,Y); 
samer@32: end
samer@32: 
samer@32: function z=sm(y)
samer@32: 	z=conv(h,y); % complete convolution
samer@32: 	z=z(i:end-(m-i)); % trim the ends
samer@32: 
samer@32: 	% rescale end bits
samer@32: 	z(1:m-i)=z(1:m-i)./csh(i:end-1);
samer@32: 	z(end-i+2:end)=z(end-i+2:end)./rsh(2:i);
samer@32: end
samer@32: 
samer@32: end