bionic (3) pcdbtrf.3.gz

NAME

       PCDBTRF  -  compute  a  LU factorization of an N-by-N complex banded diagonally dominant-like distributed
       matrix with bandwidth BWL, BWU

SYNOPSIS

       SUBROUTINE PCDBTRF( N, BWL, BWU, A, JA, DESCA, AF, LAF, WORK, LWORK, INFO )

           INTEGER         BWL, BWU, INFO, JA, LAF, LWORK, N

           INTEGER         DESCA( * )

           COMPLEX         A( * ), AF( * ), WORK( * )

PURPOSE

       PCDBTRF computes a LU factorization of an N-by-N  complex  banded  diagonally  dominant-like  distributed
       matrix  with  bandwidth  BWL,  BWU: A(1:N, JA:JA+N-1).  Reordering is used to increase parallelism in the
       factorization.  This reordering results in factors that are DIFFERENT from those produced  by  equivalent
       sequential codes. These factors cannot be used directly by users; however, they can be used in
       subsequent calls to PCDBTRS to solve linear systems.

       The factorization has the form

               P A(1:N, JA:JA+N-1) P^T = L U

       where  U  is  a  banded  upper triangular matrix and L is banded lower triangular, and P is a permutation
       matrix.