aa1_differences

function TFD = Fdiff(X, Y)
    %% Input::
    % X = [ x0 x1 .. xn ] - object vector
    % Y = [ y0 y1 .. yn ] - image vector
    %% Output:
    %   TFD - table of forward differences
    [p, m ] = size(X); % m points, polynomial order <= m-1
    if p ~= 1 || p ~=size(Y, 1) || m ~= size(Y, 2)
        error('divdiff: input vectors must have the same dimension');
    end
    TFD = zeros(m, m);
    TFD(:, 1) = Y';
    for j = 2 : m
        for i = 1 : (m - j + 1)
            TFD(i,j) = (TFD(i + 1, j - 1) - TFD(i, j - 1));
        end
    end
end