PZPTTRF(l) ) PZPTTRF(l)NAME
PZPTTRF - compute a Cholesky factorization of an N-by-N complex tridi‐
agonal symmetric positive definite distributed matrix A(1:N, JA:JA+N-1)
SYNOPSIS
SUBROUTINE PZPTTRF( N, D, E, JA, DESCA, AF, LAF, WORK, LWORK, INFO )
INTEGER INFO, JA, LAF, LWORK, N
INTEGER DESCA( * )
COMPLEX*16 AF( * ), E( * ), WORK( * )
DOUBLE PRECISION D( * )
PURPOSE
PZPTTRF computes a Cholesky factorization of an N-by-N complex tridiag‐
onal 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 in
subsequent calls to PZPTTRS 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.
ScaLAPACK version 1.7 13 August 2001 PZPTTRF(l)