To approach this problem, you can create an array to store the variance values, and then update the appropriate element of the array at each iteration of the loop. See the below example:
% Define the size of the variance array
variance_array = zeros(1, 200);
% Loop through the 200 elements
for i = 1:200
% Calculate the variance for the current element. replace this function
% with whatever that calculates the variance.
variance = calculate_variance(i);
% Store the variance value in the appropriate element of the variance array
variance_array(i) = variance;
end
% Find the element with the greatest variance
[~, max_variance_index] = max(variance_array);
% Plot the gradient for the element with the greatest variance
plot_gradient(max_variance_index);
