bionic (3) pzpttrf.3.gz

NAME

       PZPTTRF  -  compute a Cholesky factorization of an N-by-N complex tridiagonal 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 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 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.