Q is a projection matrix, which is used to calculate the principal component Y of the original matrix X.

Y = Q^T*X, and there exists a cvx problem that

*variable Q(m,n)*

*maximize(trace(Q’*A*A’*Q))*

*subject to*

*Q’*Q == I*

I is a unit matrix

and the matlab shows the below error：

Disciplined convex programming error for the code “*maximize(trace(Q’*A*A’*Q))*”:

Only scalar quadratic forms can be specified in CVX