PCPTTRF(3)    ScaLAPACK routine of NEC Numeric Library Collection   PCPTTRF(3)



NAME
       PCPTTRF  - 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 PCPTTRF( N, D, E, JA, DESCA, AF, LAF, WORK, LWORK, INFO )

           INTEGER         INFO, JA, LAF, LWORK, N

           INTEGER         DESCA( * )

           COMPLEX         AF( * ), E( * ), WORK( * )

           REAL            D( * )

PURPOSE
       PCPTTRF 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 PCPTTRS 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 routine               31 October 2017                     PCPTTRF(3)