NAME
PCDTTRF - compute a LU factorization of an N-by-N complex tridiagonal
diagonally dominant-like distributed matrix A(1:N, JA:JA+N-1)
SYNOPSIS
SUBROUTINE PCDTTRF( N, DL, D, DU, JA, DESCA, AF, LAF, WORK, LWORK, INFO
)
INTEGER INFO, JA, LAF, LWORK, N
INTEGER DESCA( * )
COMPLEX AF( * ), D( * ), DL( * ), DU( * ), WORK( * )
PURPOSE
PCDTTRF computes a LU factorization of an N-by-N complex 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 PCDTTRS 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.