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NAME

       PSDTTRF  -  compute  a  LU  factorization of an N-by-N real tridiagonal
       diagonally dominant-like distributed matrix A(1:N, JA:JA+N-1)

SYNOPSIS

       SUBROUTINE PSDTTRF( N, DL, D, DU, JA, DESCA, AF, LAF, WORK, LWORK, INFO
                           )

           INTEGER         INFO, JA, LAF, LWORK, N

           INTEGER         DESCA( * )

           REAL            AF( * ), D( * ), DL( * ), DU( * ), WORK( * )

PURPOSE

       PSDTTRF  computes  a  LU  factorization  of  an N-by-N real 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 PSDTTRS 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.