# Expression for Shannon Capacity of Wireless channel in CVX

Hi,
I tried to maximize the following objective function

C=w_ilog(1+A wi), w_i and A are matrices

in CVX, but failed due to the ----\textit{Cannot perform the operation: {real affine} .* {concave}}---- error.

You have something similar in the the predefined functions (the entropy, which is xlog(x)), is there a way for this objective function to be rewritten?

G.L
Amin

Hi,
Thanks to the comment in here
x\log(1+1/x) using CVX

it can be implemented in CVX.

Thank you MCG…

What are the dimensions of your variables (matrices)? Is your objective function even a scalar?