DragonFly On-Line Manual Pages

PSDTTRF(l)                             )                            PSDTTRF(l)

NAME
       PSDTTRF - compute a LU factorization of an N-by-N real tridiagonal
       diagonally dominant-like distributed matrix A(1:N, JA:JA+N-1)

SYNOPSIS
       SUBROUTINE PSDTTRF( N, DL, D, DU, JA, DESCA, AF, LAF, WORK, LWORK, INFO
                           )
           INTEGER INFO, JA, LAF, LWORK, N
           INTEGER DESCA( * )
           REAL AF( * ), D( * ), DL( * ), DU( * ), WORK( * )

PURPOSE
       PSDTTRF computes a LU factorization of an N-by-N real tridiagonal
       diagonally dominant-like 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 in
       subsequent calls to PSDTTRS 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 tridiagonal upper triangular matrix and L is tridiagonal
       lower triangular, and P is a permutation matrix.

ScaLAPACK version 1.7           13 August 2001                      PSDTTRF(l)