# Cannot perform the operation: {positive constant} ./ {convex}

it told me that this row z2= z2+A(k,i)(p0^2)./(H^2+C2(i)) exists mistake as shown in the title
cvx_begin
expression C2(2
K,1);
variable q(2,1);
expression R_UAV_K(1,2K);
expression R_K_UAV(1,2
K);
expression R_min(2K,1);
for k=1:1:2
K

``````    P(k)=1;
U(: , k)=[x_user(k);y_user(k)];
XL(k)=norm(U(:,k)-qL(:,1))^2;
d(k)=(H^2+XL(k));
h(k)= p0./sqrt(d(k));
C2(k)=pow_pos(norm(U(:,k)-q(: ,1)),2);
end
fai=sigma./(P_UAV*(p0^2));
delta=zeros(2*K,1);
z1=0;
for k=1:1:2*K
for i=1:1:2*K
z1=z1+b_down(i)*B(k,i);
end
delta(k)=fai*(H^2)+z1;
R_UAV_K(k)= log2(1+b_down(k)./(delta(k)+fai*XL(k)))-b_down(k)*fai*(C2(k)-XL(k))./((log(2))*(delta(k)+b_down(k)+fai*XL(k))*(delta(k)+fai*XL(k)));
end

z2=0;
tao=zeros(1,2*K);
for k=1:1:2*K
for i=1:1:2*K
if A(k,i)~=0
z2= z2+A(k,i)*(p0^2)./(H^2+C2(i));
end
end
tao(k)=z2;
R_K_UAV(k)=log2(1+P(k)*p0^2./((tao(k)+sigma)*(H^2+XL(k))))-p0^2*P(k)*(C2(k)-XL(k))./(log(2)*(H^2+XL(k))*(H^2+XL(k)+p0^2*P(k)));
end

for k=1:1:2*K
R_min(k)=min( R_K_UAV(2*K-k+1),R_UAV_K(k));
end

maximize  (sum(R_min))
subject to
for k=1:1:2*K
for i=1:1:2*K
if A(k,i)==1
%C2(k)<=C2(i);
pow_pos(norm(U(:,k)),2)-pow_pos(norm(U(:,i)),2)+2*q(1,1)*(U(1,i)-U(1,k))+2*q(2,1)*(U(2,i)-U(2,k))<=0;
end
end
end

cvx_end

qL=q;
scatter(qL(1,1),qL(2,1),260,'m','p','filled');
``````

end

`z2` goes into `tao` which goes into `R_K_UAV`, which needs to be concave. So you need to first prove that ` R_K_UAV` is concave.

Why does your code set ` R_K_UAV(k)` in 2 different double for loops?

I am sorry to say that R_K_UAV is convex

`R_K_UAV` is used as the argument of `min`, so it needs to be concave, which would make the argument of maximize in the objective concave, which is needed to make the optimization problem convex.