If I have a diagonal matrix, its main diagonal elements are e**(1jx) where x is the optimizable variable between 0 and 2pi, something like this: Matrix_of_X = np.diag(e**(1j*x)) How to use the CVX tool provided by python in this link: https://www.cvxpy.org/
for example the objective function is to maximize the trace of this diagonal matrix
it seems that this library accept only polynomial equations for x.