PCDBTRF(3)    ScaLAPACK routine of NEC Numeric Library Collection   PCDBTRF(3)



NAME
       PCDBTRF - compute a LU factorization of an N-by-N complex banded diago-
       nally 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 diago-
       nally dominant-like distributed matrix with bandwidth BWL, BWU:  A(1:N,
       JA:JA+N-1).  Reordering  is used to increase parallelism in the factor-
       ization.  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  tri-
       angular, and P is a permutation matrix.




ScaLAPACK routine               31 October 2017                     PCDBTRF(3)