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PDDBTRF(l)			       )			    PDDBTRF(l)

NAME
       PDDBTRF	-  compute  a LU factorization of an N-by-N real banded	diago-
       nally dominant-like distributed matrix with bandwidth BWL, BWU

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

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

	   INTEGER	   DESCA( * )

	   DOUBLE	   PRECISION A(	* ), AF( * ), WORK( * )

PURPOSE
       PDDBTRF computes	a LU factorization of an N-by-N	real 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 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 PDDBTRS 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 version 1.7		13 August 2001			    PDDBTRF(l)

NAME | SYNOPSIS | PURPOSE

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