# Invalid quadratic form:not a square

I have always have a problem to solve the following question

``````cvx_begin sdp quiet
variable W(Nt,Nt,Rx) hermitian
variables a t211 r111 r211  t212 r112 r212 t121 r221 r121 t122 r222 r122 t21 ra1 ra2 t11 rb2 rb1
sum=0;
for f=1:Rx
sum=sum+W(:,:,f)
end
min sum
subject to
A=[W(:,:,1)-a*z*W(:,:,2)+r111*eye(2),(W(:,:,1)-a*z*W(:,:,2))*h111;h111'*(W(:,:,1)-a*z*W(:,:,2)),h111'*(W(:,:,1)-a*z*W(:,:,2)-z*a*t211-z*a*sigmma-r111)]
A1==hermitian_semidefinite(3);
cvx_end
``````

error:

``````Error using ==> cvx.times at 262
Disciplined convex programming error:
Invalid quadratic form(s): not a square.
Error in ==> Untitled3 at 64
A=[W(:,:,1)-a*z*W(:,:,2)+r111*eye(2),(W(:,:,1)-a*z*W(:,:,2))*h111;h111'*(W(:,:,1)-a*z*W(:,:,2)),h111'*(W(:,:,1)-a*z*W(:,:,2)-z*a*t211-z*a*sigmma-r111)];
``````

Incidentally, for the benefit of others, you should be saying `minimize(sum)`, not `min sum`. And it would seem that `sum` is not a scalar, so your objective function is ill-posed. but I’m afraid that’s moot.