Cannot perform the operation: {convex} .* {concave}

I try to solve objective function which contains something like f(x)/g(x) using fractional programming methods such as dinkelbach algorithm. But, I deal with this error in running the body of dinkelbach:

Error using .* (line 173)
Disciplined convex programming error:
Cannot perform the operation: {convex} .* {concave}

Error in dinkle (line 18)

note that zeta is cvx convex expression, phi is affine and say is concave.

You need to follow CVX’s rules. Try looking at the fractional programming material in and search for fractional on this forum.