PCPBTRF(l) ) PCPBTRF(l)NAME
PCPBTRF - compute a Cholesky factorization of an N-by-N complex banded
symmetric positive definite distributed matrix with bandwidth BW
SYNOPSIS
SUBROUTINE PCPBTRF( UPLO, N, BW, A, JA, DESCA, AF, LAF, WORK, LWORK,
INFO )
CHARACTER UPLO
INTEGER BW, INFO, JA, LAF, LWORK, N
INTEGER DESCA( * )
COMPLEX A( * ), AF( * ), WORK( * )
PURPOSE
PCPBTRF computes a Cholesky factorization of an N-by-N complex banded
symmetric positive definite distributed matrix with bandwidth BW:
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 can‐
not be used directly by users; however, they can be used in
subsequent calls to PCPBTRS to solve linear systems.
The factorization has the form
P A(1:N, JA:JA+N-1) P^T = U' U , if UPLO = 'U', or
P A(1:N, JA:JA+N-1) P^T = L L', if UPLO = 'L'
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 PCPBTRF(l)
