slow function about cimmino calculation

Hello ! I made a function to find the cimmino solution ( its about Computerized Tomography) but my function is really slow. From profiler i saw that the problem is in this part:

M = size(A,1);

d=zeros(M,1);

M_sq = sqrt(M);

for ii = 1:M

    n = normest(A(ii,:));
    if n~=0
        d(ii) = 1/(M_sq*n);
    end
end

Anyone has any idea to make it more efficient? In a typical run : A < 63616x2500 sparse double >

Thank you,Dimitris