cptts2()

subroutine cptts2	(	integer	iuplo,
		integer	n,
		integer	nrhs,
		real, dimension( * )	d,
		complex, dimension( * )	e,
		complex, dimension( ldb, * )	b,
		integer	ldb )

CPTTS2 solves a tridiagonal system of the form AX=B using the L D LH factorization computed by spttrf.

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Purpose:

!>
!> CPTTS2 solves a tridiagonal system of the form
!>    A * X = B
!> using the factorization A = U**H*D*U or A = L*D*L**H computed by CPTTRF.
!> D is a diagonal matrix specified in the vector D, U (or L) is a unit
!> bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
!> the vector E, and X and B are N by NRHS matrices.
!> 

Parameters

[in]	IUPLO	!> IUPLO is INTEGER !> Specifies the form of the factorization and whether the !> vector E is the superdiagonal of the upper bidiagonal factor !> U or the subdiagonal of the lower bidiagonal factor L. !> = 1: A = U**H *D*U, E is the superdiagonal of U !> = 0: A = L*D*L**H, E is the subdiagonal of L !>
[in]	N	!> N is INTEGER !> The order of the tridiagonal matrix A. N >= 0. !>
[in]	NRHS	!> NRHS is INTEGER !> The number of right hand sides, i.e., the number of columns !> of the matrix B. NRHS >= 0. !>
[in]	D	!> D is REAL array, dimension (N) !> The n diagonal elements of the diagonal matrix D from the !> factorization A = U**H *D*U or A = L*D*L**H. !>
[in]	E	!> E is COMPLEX array, dimension (N-1) !> If IUPLO = 1, the (n-1) superdiagonal elements of the unit !> bidiagonal factor U from the factorization A = U**H*D*U. !> If IUPLO = 0, the (n-1) subdiagonal elements of the unit !> bidiagonal factor L from the factorization A = L*D*L**H. !>
[in,out]	B	!> B is COMPLEX array, dimension (LDB,NRHS) !> On entry, the right hand side vectors B for the system of !> linear equations. !> On exit, the solution vectors, X. !>
[in]	LDB	!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(1,N). !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.