In which A is a Hermitian matrix.

The error occurs as: Disciplined convex programming error:

Only scalar quadratic forms can be specified in CVX

I was wondering if it is possible to solve it via CVX ?

Apply the same transformation as in this answer you “liked” Help me for this objective function .

`maximize(-square_pos(norm(sqrtm(A)*X,'fro')))`

The argmax is preserved if instead you use `maximize(-norm(sqrtm(A)*X,'fro'))`

which avoids unnecessary squarng, and might be better behaved numerically.

Thank you very much，I am a newbie in this community, and I found your answer after I asked the question. It realy helps a lot in my work.

Best wishes .