code 34240;
    real procedure ONENRMINV(A, N); value N; integer N;
    array A;
    begin integer I, J;
        real NORM, MAX, AID;
        array Y[1:N];
        NORM:= 0;
        for J:= 1 step 1 until N do 
        begin for I:= 1 step 1 until N do Y[I]:= if I < J
            then 0 else if I = J then 1 / A[I,I] else 
            - MATVEC(J, I - 1, I, A, Y) / A[I,I];
            MAX:= 0;
            for I:= N step - 1 until 1 do 
            begin AID:= Y[I]:= Y[I] - MATVEC(I + 1, N, I, A, Y);
                MAX:= MAX + ABS(AID)
            end;
            if NORM < MAX then NORM:= MAX
        end;
        ONENRMINV:= NORM
    end ONENRMINV;
        eop