the (if statement) condition happens only ones but I want to repeat this if (F Zero) is still not empty

      if (~isempty(F_Zero)) %There is Zeros (not empty)
       W(:,F_Zero) = [];  % Remove the columns of W
       HT(F_Zero,:) = []; % Remove the rows of HT

       W_bar = W./sqrt(sum(abs(W.^2),1));
       D_Matrix = HT*W_bar; %Diagonal Matrix
       D_Square = (abs(diag(D_Matrix))').^2; % Channel gains
       P = waterfill(Pt,Pn./D_Square);
       F_Zero=find(~P);
      else
      % do Nothing
      end 

[Mouhamed Niasse]

https://www.mathworks.com/help/matlab/ref/while.html?s_tid=srchtitle

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[KSSV]

If you are looking for a loop, you may go for while loop.

while ~isempty(F_Zero)
    % Do what you want 
end