How to use CVX to solve feasibility problem?


This is my problem. R and W is variable. R is a scalar, W and Fk is a symmetric positive semidefinite matrix, To tackle the coupled variables R and W, I decide to use the bisection search method to solve the problem. Specifically, I will replace R in problem by a constant, and solve the resulting feasibility problem reduced from the problem. But I don’t know how to express the problem in CVX when the optimization objective is a constant.

Maybe you are not showing everything but this looks like all conditions here are linear so you have a straightforward SDP without the need to decouple anything.

In my opinion, the constraint of (9b) is non-convex because of the coupled variables R and W.

A feasibility problem can be specified by not including minimize or maximize (objective).

Of course. I missed one of the R

Ok, thank you very much for your reply!

Thanks for your reply!

@ccsnow 您好,打扰您一下,我也遇到您这种类似的可行性问题,可以分享一下这部分的代码吗,十分感谢!!!

A feasibility problem can be specified by not including minimize or maximize (objective), as shown below.
cvx_begin sdp
variable Theta(N_RIS,N_RIS) hermitian semidefinite;
subject to
for n = 1:N_RIS
Theta_W(n,n) == 1;
end
A feasibility problem can also be specified by including minimize 0, as shown below.
cvx_begin sdp
variable Theta(N_RIS,N_RIS) hermitian semidefinite;
minimize 0
subject to
for n = 1:N_RIS
Theta_W(n,n) == 1;
end

@ccsnow
您好,您这个是上面非凸问题全部代码吗,这里面的目标函数以及二分搜索法在哪里体现呢?约束前两个在哪里体现呢?

No, this is not complete code, I just want to show how to express the feasibility problem.

@wujunyi This is an English language forum. Please make any additional posts in English. Use Google translate or some other tool if you need to, perhaps with a disclaimer if you are not sure how good the translation is.

If you need to communicate with a poster using a language other than English, please use the forum Message capability, i.e., PM.

ok.I’ll pay attention

Hi Mark, could you please consider the question in this post, it is also about feasibility problems:

Hi Michal, could you please consider the question in this post, it is also about feasibility problems: