TY - RPRT TI - An Approximate Direct Inverse as a Preconditioner For Ill-Conditioned Problems. AU - Lee, Chung Hyun AU - Lee, Jin-Fa AU - Langston, William L. AU - Zinser, Brian Frederick AU - Dang, Vinh Quang AU - Huang, Andy AU - Campione, Salvatore PY - 2020 UR - https://www.osti.gov/biblio/1806260 ID - 1806260 ER -