variable phi(3,1) complex
For the above problem, I found that the outer product (x*x’) is not allowed in CVX. The error is shown as
Disciplined convex programming error: Invalid quadratic form(s): not a square.
What’s the meaning of this error and how can I express outer product in object and constraints?
Using the cyclic permutation invariance of trace, the objective can be rewritten as
square_pos(norm(a'*phi)), which can be replaced by
norm(a'*phi) because it has the same argmin.
Your semidefintie constraint, as written, is a Bilinear Matrix Inequality (BMI) constraint, which is non-convex and not allowed by CVX.
See my answer to your previous question ERROR:Disciplined convex programming error: Only scalar quadratic forms can be specified in CVX . Did you not learn from that answer?
The link below was also provided in my answer to your previous question. Perhaps you did not read it carefully enough?