function v=unitvector(i,n)

%Generate a unit column vector of size n with 1 at the ith entry.  Here, n
%is greater than 1.

if (i==1)
    v=[1;zeros(n-1,1)];
else
    if (i==n)
        v=[zeros(n-1,1);1];
    else
        v=[zeros(i-1,1);1;zeros(n-i,1)];
    end
end