PDDTTRSV - solve a tridiagonal triangular system of linear equations A(1:N, JA:JA+N-1) * X =

       PDDTTRSV  -  solve  a  tridiagonal  triangular  system  of  linear  equations    A(1:N,  JA:JA+N-1) * X =
       B(IB:IB+N-1, 1:NRHS)

       PDDTTRSV solves a tridiagonal triangular system of linear equations
                                      or
                           A(1:N, JA:JA+N-1)^T * X = B(IB:IB+N-1, 1:NRHS)

       where A(1:N, JA:JA+N-1) is a tridiagonal
       triangular matrix factor produced by the
       Gaussian elimination code PD@(dom_pre)TTRF
       and is stored in A(1:N,JA:JA+N-1) and AF.
       The matrix stored in A(1:N, JA:JA+N-1) is either
       upper or lower triangular according to UPLO,
       and the choice of solving A(1:N, JA:JA+N-1) or A(1:N,  JA:JA+N-1)^T  is  dictated  by  the  user  by  the
       parameter TRANS.

       Routine PDDTTRF MUST be called first.

LAPACK version 1.5                                 12 May 1997                                       PDDTTRSV(l)

       SUBROUTINE PDDTTRSV( UPLO, TRANS, N, NRHS, DL, D, DU, JA, DESCA, B, IB, DESCB, AF, LAF, WORK, LWORK, INFO
                            )

           CHARACTER        TRANS, UPLO

           INTEGER          IB, INFO, JA, LAF, LWORK, N, NRHS

           INTEGER          DESCA( * ), DESCB( * )

           DOUBLE           PRECISION AF( * ), B( * ), D( * ), DL( * ), DU( * ), WORK( * )