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