function [M, I] = maxIdx(Vec)
%tail   Calculate the max,index pair of each Vec(:)
%
    n = length(Vec);
    I = 0;
    M = -1;
    for j = 1:n
        if M < Vec(j)
            M(j) = Mat(i,j);
            I(j) = i;
        end
    end
end