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)
