function A = construct(m, n, f) % % Construct an m-by-n matrix with entries a_ij = f(i,j). % if ((m < 0) || (n < 0)) A = NA; return; elseif ((m == 0) || (n == 0)) A = NA; return; end A = zeros(m,n); for i = [ 1 : m ] for j = [ 1 : n ] A(i,j) = f(i,j); end end end