```
%g_AB , P_C2AB , P_B2AC , g_A , P_A2BC, N_0, mu are all constant
cvx begin
variable rho_stA semidefinite
SINR_stAB=( (1-rho_stA)*g_AB*P_B2AC )/...
( (1-rho_stA)*g_AC *P_C2AB +(1-rho_stA)*g_A*P_A2BC + (1-rho_stA)*N_0+mu*N_0 )
subject to .....
```

The command window show me this error :

`Disciplined convex programming error: Cannot perform the operation: {real affine} ./ {real affine}`

So when i want to declare a parameter , SINR_stAB , which is a fraction,if i want to let the cvx accept this,what type of numerator and denominator should be ? both convex ? or?

Now i just know numerator and denominator both can’t be real affine , i mean real linear