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)

fun=(1/n)*sum(phi(Ptrans)-zeta(l,:).*say(Ptrans));

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