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.