debian man page for pdpbtrf

PDPBTRF(l)						   LAPACK routine (version 1.5) 						PDPBTRF(l)

NAME
       PDPBTRF - compute a Cholesky factorization of an N-by-N real banded symmetric positive definite distributed matrix with bandwidth BW

SYNOPSIS
       SUBROUTINE PDPBTRF( UPLO, N, BW, A, JA, DESCA, AF, LAF, WORK, LWORK, INFO )

	   CHARACTER	   UPLO

	   INTEGER	   BW, INFO, JA, LAF, LWORK, N

	   INTEGER	   DESCA( * )

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

PURPOSE
       PDPBTRF computes a Cholesky factorization of an N-by-N real 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 PDPBTRS 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 							PDPBTRF(l)