Can anyone vectorize this (as I can't)...  Also, any help understanding
how you worked it out would also be appreciated...  Thanks.
-Steve

M is NxN (and values are integers in range 0-8)
P is NxN (and values are integers in range 1-8)
-------------------------------------------------
H=zeros(N*8,N*8);
H_p_rev=H;

for n=1:N
    for m=1:N
        if M(m,n)~=0
               H((8*m-M(m,n)+1):8*m,8*n-8+P(m,n))=1;
               H_p_rev((8*m-M(m,n)+1):8*m,(8*n)+1-P(m,n))=1;
        end
    end
end

Hi,

you can simply avoid to use the if condition :

for n=1:N
    for m=1:N
H((8*m-M(m,n)+1):8*m,8*n-8+P(m,n))=(M(m,n)~=0);
H_p_rev((8*m-M(m,n)+1):8*m,(8*n)+1-P(m,n))=(M(m,n)~=0);
    end
end

It's not vectorized but it should be faster.

J�r�me

Why did I say faster ?
I need to drink my second coffee :-x

J�r�me