Provided by: scalapack-doc_1.5-10_all

**NAME**

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

**SYNOPSIS**

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( * )

**PURPOSE**

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.