zpttrs(3F)

NAME
     ZPTTRS - solve a system of linear equations A * X = B with a Hermitian
     positive definite tridiagonal matrix A using the factorization A =
     U**H*D*U or A = L*D*L**H computed by ZPTTRF

SYNOPSIS
     SUBROUTINE ZPTTRS( UPLO, N, NRHS, D, E, B, LDB, INFO )

         CHARACTER      UPLO

         INTEGER        INFO, LDB, N, NRHS

         DOUBLE         PRECISION D( * )

         COMPLEX*16     B( LDB, * ), E( * )

PURPOSE
     ZPTTRS solves a system of linear equations A * X = B with a Hermitian
     positive definite tridiagonal matrix A using the factorization A =
     U**H*D*U or A = L*D*L**H computed by ZPTTRF.


ARGUMENTS
     UPLO    (input) CHARACTER*1
             Specifies whether the superdiagonal or the subdiagonal of the
             tridiagonal matrix A is stored and the form of the factorization:
             = 'U':  E is the superdiagonal of U, and A = U'*D*U;
             = 'L':  E is the subdiagonal of L, and A = L*D*L'.  (The two
             forms are equivalent if A is real.)

     N       (input) INTEGER
             The order of the tridiagonal matrix A.  N >= 0.

     NRHS    (input) INTEGER
             The number of right hand sides, i.e., the number of columns of
             the matrix B.  NRHS >= 0.

     D       (input) DOUBLE PRECISION array, dimension (N)
             The n diagonal elements of the diagonal matrix D from the
             factorization computed by ZPTTRF.

     E       (input) COMPLEX*16 array, dimension (N-1)
             The (n-1) off-diagonal elements of the unit bidiagonal factor U
             or L from the factorization computed by ZPTTRF (see UPLO).

     B       (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
             On entry, the right hand side matrix B.  On exit, the solution
             matrix X.

     LDB     (input) INTEGER
             The leading dimension of the array B.  LDB >= max(1,N).
     INFO    (output) INTEGER
             = 0:  successful exit
             < 0:  if INFO = -i, the i-th argument had an illegal value