Incomplete upper triangular factor had 1 zero diagonal replaced by local drop tolerance. It may not make a good preconditioner for an iterative method. Incomplete upper triangular factor had {0,number,integer} zero diagonals replaced by local drop tolerance. It may not make a good preconditioner for an iterative method. Incomplete upper triangular factor has 1 zero diagonal. It cannot be used as a preconditioner for an iterative method. Incomplete upper triangular factor has {0,number,integer} zero diagonals. It cannot be used as a preconditioner for an iterative method.