MATLAB: Replace specific/diagonal elements in Matrix using editor, scripting

diagonalmatricesmatrix manipulationreplacing specific values in matrix to 0

Hello,
Looking a simple way to replace diagonal values in vector to 0. The matrix is a variance-covariance matrix, however in system will be assuming covariance are
zero, and are independent to each. Have the following matrix:
A = [ 2.5 0.25; 0.25 2.4]
B = flip(A) %Flipped to get in correct orientation to select diagonals 0.25, 0.25
%Not sure if it is possible to select mirrored diagonal in original matrix A
Covariance values are 0.25, which would like to set to zero. However these value could change, therefore if had method to replace these diagonal values with respect to m-row, n-column position, or other method?
If can be selected from original matrix A, would be ideal to avoid flipping.
Thanks in advance
kind rgds

Best Answer

% If this is to be called iteratively
% Example while loop
iteration = 0;
while (iteration < numel(data)) % Some conditional to stay in your loop
    if ~iteration
        % Initially
        % A = [2.5 0; 0 2.4]; % Can you just initialize it with zeros?
        
        % Alternatively, suppose it was imported elsewhere:
        A = [ 2.5 0.25; ... % Top right = A(1,2);
              0.25 2.4];    % Bottom left = A(2,1);
        A = diag(diag(A)); % Keep only diagonal elements
    else
        A(1,2) = cov_ab; % Assume you get this from elsewhere
        A(2,1) = cov_ba;
    end 
    ...
    % Get covariance values 
    doc cov % May be helpful
    ...
    iteration = iteration + 1;
end
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