Rechercher une page de manuel
pdpttrf
Langue: en
Version: 298052 (debian - 07/07/09)
Section: 3 (Bibliothèques de fonctions)
NAME
PDPTTRF - compute a Cholesky factorization of an N-by-N real tridiagonal symmetric positive definite distributed matrix A(1:N, JA:JA+N-1)SYNOPSIS
- SUBROUTINE PDPTTRF(
- N, D, E, JA, DESCA, AF, LAF, WORK, LWORK, INFO )
- INTEGER INFO, JA, LAF, LWORK, N
- INTEGER DESCA( * )
- DOUBLE PRECISION AF( * ), D( * ), E( * ), WORK( * )
PURPOSE
PDPTTRF computes a Cholesky factorization of an N-by-N real tridiagonal symmetric positive definite distributed matrix 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 insubsequent calls to PDPTTRS to solve linear systems.
The factorization has the form
P A(1:N, JA:JA+N-1) P^T = U' D U or
P A(1:N, JA:JA+N-1) P^T = L D L',
where U is a tridiagonal upper triangular matrix and L is tridiagonal lower triangular, and P is a permutation matrix.
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre