pcpbtrf(3) debian man page | unix.com

PCPBTRF(l)						   LAPACK routine (version 1.5) 						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 cannot 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 triangular, and P is a permutation matrix.

LAPACK version 1.5						    12 May 1997 							PCPBTRF(l)