function [Q,R]=gram2(A,B)
    [m,n]=size(B);
    if n==1 then
        a=sqrt(B'*A*B)
        Q=B/a;
        R=a;
    else
        [Q,R]=gram2(A,B(:,1:(n-1)));
        C1=Q'*A*B(:,n);
        C=B(:,n)-Q*C1;
        a=sqrt(C'*A*C);
        C=C/a;
        Q=[Q C];
        R=[R C1;zeros(1,n-1) a]
    end
endfunction