<t>QuoteOriginally posted by: AlanQuoteYour formula should work. If A = Q'*Diag(lambda1, ..., lambdan)*Q, where Q is an orthogonal matrix, then I-A = Q'*I*Q-Q'*diag(lambda1, ..., lambdan)*Q=Q'*diag(1-lambda1, ..., 1-lambdan)*Q -> inv(I-A)=Q'*diag(1/(lambda1-1), ..., 1/(lambdan-1))*Q. What about rho ...