Hi I am try to run the following CVX but received an error about

```
Disciplined convex programming error:
Cannot perform the operation: {complex affine} .* {concave}
```

This error occur in the line of ‘Maximize’

My CVX is shown as follow:

```
cvx_begin
variable W_b(N_t,N_t) complex semidefinite;
maximize (log(2*y1*sqrt(1+real(p*alpha*G1*h2'*W_b*h2))-y1^2*(1+p*alpha*abs(g2)^2/q*h2'*W_b*h2/real(ones(N_e,1)'*X*ones(N_e,1)) ) )/log(2))
subject to
trace(W_b)<=1;
0<=phi;
phi<=1;
2*y2*sqrt(p*h2'*W_b*h2)-y2^2*(1+p*alpha*abs(g1)^2*h2'*W_b*h2)>=gamma_s_th;
cvx_end
```

You can treat all parameters are known except the variable `W_b`

. Any suggestions are much appreciated!