Kershaw's example for breakdown of incomplete Cholesky                   KERSHAW
             3             1             1             1             0
RUA                        4             4            12             0
          (12i5)          (12i5)            (12f5.0)            (12f5.0)
    1    4    7   10   13
    1    2    4    1    2    3    2    3    4    1    3    4
   3.  -2.   2.  -2.   3.  -2.  -2.   3.  -2.   2.  -2.   3.