chenchen
(chenchen)
1
```
cvx_begin
variable e(N,1) complex
minimize ((vs+e)'*inv(Rc)*(vs+e))
subject to
vs'*e==0
(vs+e)'*inv(Rc)*(vs+e)<= vs'*inv(Rc)*vs
cvx_end
```

vs and e are N*1 complex vector，Rc is a N*N comlpex matrix.

Disciplined convex programming error:

Invalid quadratic form: product is complex.

I think the problem is due to round-off level imaginary terms in quadratic forms. It seems thhat CVX is rather fussy.

The following worked for me on a test problem I tried:

```
cvx_begin
variable e(N,1) complex
minimize (quad_form(vs+e,inv(Rc)))
subject to
vs'*e==0
quad_form(vs+e,inv(Rc)) <= quad_form(vs,inv(Rc))
cvx_end
```

`real(vs'*inv(Rc)*vs)`

can be used instead of `quad_form(vs,inv(Rc))`

and accomplishes eliminating the round-off level imaginary component.