# Matix multiplication in CVX

Hi, all,

I’m trying to implement the following constrain into CVX, but I encountered with lots of problems of the syntax of CVX.

\sum_{j=1}^{L}\sum_{i=1}^{N} (1+r_j)\rho_j w_{ij}^Hw_{ij} \leq \mathbf{S},

where \rho_j and w_{ij} are the variables. w_{ij} is a vector, which belongs to the block matrix W(N,L). \rho,r are vectors with L rows.

I’ve tried to implement it with the following code:

“norm(w*diag((1+r).*rho)) <=S”, but there is an error:

“Disciplined convex programming error:
Only scalar quadratic forms can be specified in CVX.”

Can anyone tell me the right way to implement? Many thanks!

Regards,

Armstrong

This problem is not convex. CVX cannot solve it.

Yes. Thanks.