Daniel@0: function M = setdiag(M, v)
Daniel@0: % SETDIAG Set the diagonal of a matrix to a specified scalar/vector.
Daniel@0: % M = set_diag(M, v)
Daniel@0: 
Daniel@0: n = length(M);
Daniel@0: if length(v)==1
Daniel@0:   v = repmat(v, 1, n);
Daniel@0: end
Daniel@0: 
Daniel@0: % e.g., for 3x3 matrix,  elements are numbered
Daniel@0: % 1 4 7 
Daniel@0: % 2 5 8 
Daniel@0: % 3 6 9
Daniel@0: % so diagnoal = [1 5 9]
Daniel@0: 
Daniel@0: 
Daniel@0: J = 1:n+1:n^2;
Daniel@0: M(J) = v;
Daniel@0: 
Daniel@0: %M = triu(M,1) + tril(M,-1) + diag(v);
Daniel@0: