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



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 diag-
       onally 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; how-
       ever, 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.




ScaLAPACK routine               31 October 2017                     PSDTTRF(3)