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NAME

       PCPTTRF  -  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 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
       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 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.