Disciplined convex programming error: Invalid quadratic form: product is complex

Nonconvex
1

I am new to CVX and i tried the following optimization problem:

cvx_begin
  variables alphas(3) ;
  X12 = (alphas' * G1 *f2 * f2' *G1*alphas * Ps2)/(alphas' * G1 *K *G1*alphas + SigmaSq )
  X21 = (alphas' * G2 *f1 * f1' *G2*alphas * Ps1)/(alphas' * G2 *K *G2*alphas + SigmaSq )
  maximize(min(X12,X21));
  subject to
     alphas'*(Ps1* F1^2 +Ps2 *F2^2 + k.*eye(3))<= Psum;
cvx_end

where
Alphas=[a1 a2 a3] % variable to be optimized
f1,f2,g1,g2 are complex column vectors of 3 elements
G1=diag(g1); G2=diag(g2); F1=diag(f1); F2=diag(f2);
K = 3X3 complex matrix
SigmaSq , Psum, Ps1, Ps2 are scalar

i got the following error message for line 3 in my code
Disciplined convex programming error: Invalid quadratic form: product is complex

i read that i must put my objective function and constraints in Disciplined convex form?

can anyone help me with this problem?

2

Your problem is almost certainly not convex. And it certainly violates the DCP ruleset, which is clearly laid out in the users guide. If you cannot express your problem according to these rules, CVX simply cannot solve it. And if your problem is not convex, it cannot be written according to these rules.