func_opt_2RISs_wu.m

function [PR_wu, PR_pc] = func_opt_2RISs_wu(HT,HR,H21,typeRIS,NG)
% Optimize RIS with widely used model and evaluate on widely used and physics-compliant models

[N, NT] = size(HT);
NR = size(HR,1);
T2 = -eye(N);



PR_loop = zeros(1,1e3);
for iIter = 1:1e3

    % Optimize T1
    HR1 = HR*T2*H21;
    HT1 = HT;
    [~, T1] = func_opt_RIS_MIMO(zeros(NR,NT),HR1,HT1,typeRIS,NG);

    % Optimize T2
    HR2 = HR;
    HT2 = H21*T1*HT;
    [~, T2] = func_opt_RIS_MIMO(zeros(NR,NT),HR2,HT2,typeRIS,NG);

    % Compute PR at this iteration
    PR_loop(iIter+1) = norm(HR*T2*H21*T1*HT) ^ 2;

    % Stopping condition
    if (PR_loop(iIter+1) - PR_loop(iIter))/PR_loop(iIter) < 1e-3
        %iIter
        break;
    end
end

PR_wu = PR_loop(iIter+1);
PR_pc = norm(HR*(T2-eye(N))*H21*(T1-eye(N))*HT) ^ 2;
end