Getting Error with a [non]convex problem

when I try to solve the following problem I get the error

cvx_begin
variable v(50)

minimize(square_pos(norm(A1-v*v.’,‘Fro’))-norm(v,2))

%minimize(sum_{i,j=1}^{50} sum_square(A1(i,j)-v(i)*v(j))-sum_square(v(i)*v(i))
cvx_end

Error using * (line 126)
Disciplined convex programming error:
Only scalar quadratic forms can be specified in CVX

Any Ideas how to solve?

Thanks

You claim the problem is convex. How have you concluded that?

A1 has diagonal zero. Forget about that CVX is unable to solve minimize(square_pos(norm(A1-v*v.’,‘Fro’)).

Your claim that this problem is convex is incorrect.