## SYNOPSIS

- SUBROUTINE PDDBTRSV(
- UPLO, TRANS, N, BWL, BWU, NRHS, A, JA, DESCA, B, IB, DESCB, AF, LAF, WORK, LWORK, INFO )

- CHARACTER TRANS, UPLO

- INTEGER BWL, BWU, IB, INFO, JA, LAF, LWORK, N, NRHS

- INTEGER DESCA( * ), DESCB( * )

- DOUBLE PRECISION A( * ), AF( * ), B( * ), WORK( * )

## PURPOSE

PDDBTRSV solves a banded triangular system of linear equationsor

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 banded

triangular matrix factor produced by the

Gaussian elimination code [email protected](dom_pre)BTRF

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 PDDBTRF MUST be called first.