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7.6 PILUT: Parallel Incomplete Factorization

 

PILUT is a parallel preconditioner based on Saad's dual-threshold incomplete factorization algorithm. The original version of PILUT was done by Karypis and Kumar [&make_named_href('', "node39.html#KK1998","[9]")] in terms of the Cray SHMEM library. The code was subsequently modified by the HYPRE team: SHMEM was replaced by MPI; some algorithmic changes were made; and it was software engineered to be interoperable with several matrix implementations, including HYPRE's ParCSR format, PETSc's matrices, and ISIS++ RowMatrix. The algorithm produces an approximate factorization L U, with the preconditioner M defined by M = L U .

Note: PILUT produces a nonsymmetric preconditioner even when the original matrix is symmetric. Thus, it is generally inappropriate for preconditioning symmetric methods such as Conjugate Gradient.

Parameters:


next up previous contents index
Next: 8 Additional Information Up: 7 Solvers and Preconditioners Previous: 7.5 Euclid

Thomas Treadway
Fri Jul 27 10:01:25 PDT 2001