Norm & Illegal operation: log( {convex} )

Nonconvex
1

cvx_begin quiet
variable v_l(M,1) complex
for k=1:K
for i=i:K
h_ki=squeeze(h_rki(k,i,:))’;%默认是行
Q_A=Q_A+p(i)square_pos(norm(h_kiv_l+gdk(i),2));
end
y=y+TBlog(Q_A)/log(2);
end

error: y=y+TBlog(Q_A)/log(2);
isciplined convex programming error:
Illegal operation: log( {convex} ).
I think Q_A is convex,why is error ?

2

You cannot have nonlinear equalities if you want a convex problem.

3

Those are actually assignments, not equality constraints. So in effect just adding terms.

The error is due to log of norm squared, which is neither convex nor concave.

4

Thank you very much !!