slagtm()

subroutine slagtm	(	character	trans,
		integer	n,
		integer	nrhs,
		real	alpha,
		real, dimension( * )	dl,
		real, dimension( * )	d,
		real, dimension( * )	du,
		real, dimension( ldx, * )	x,
		integer	ldx,
		real	beta,
		real, dimension( ldb, * )	b,
		integer	ldb )

SLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

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Purpose:

!>
!> SLAGTM performs a matrix-matrix product of the form
!>
!>    B := alpha * A * X + beta * B
!>
!> where A is a tridiagonal matrix of order N, B and X are N by NRHS
!> matrices, and alpha and beta are real scalars, each of which may be
!> 0., 1., or -1.
!> 

Parameters

[in]	TRANS	!> TRANS is CHARACTER*1 !> Specifies the operation applied to A. !> = 'N': No transpose, B := alpha * A * X + beta * B !> = 'T': Transpose, B := alpha * A'* X + beta * B !> = 'C': Conjugate transpose = Transpose !>
[in]	N	!> N is INTEGER !> The order of the matrix A. N >= 0. !>
[in]	NRHS	!> NRHS is INTEGER !> The number of right hand sides, i.e., the number of columns !> of the matrices X and B. !>
[in]	ALPHA	!> ALPHA is REAL !> The scalar alpha. ALPHA must be 0., 1., or -1.; otherwise, !> it is assumed to be 0. !>
[in]	DL	!> DL is REAL array, dimension (N-1) !> The (n-1) sub-diagonal elements of T. !>
[in]	D	!> D is REAL array, dimension (N) !> The diagonal elements of T. !>
[in]	DU	!> DU is REAL array, dimension (N-1) !> The (n-1) super-diagonal elements of T. !>
[in]	X	!> X is REAL array, dimension (LDX,NRHS) !> The N by NRHS matrix X. !>
[in]	LDX	!> LDX is INTEGER !> The leading dimension of the array X. LDX >= max(N,1). !>
[in]	BETA	!> BETA is REAL !> The scalar beta. BETA must be 0., 1., or -1.; otherwise, !> it is assumed to be 1. !>
[in,out]	B	!> B is REAL array, dimension (LDB,NRHS) !> On entry, the N by NRHS matrix B. !> On exit, B is overwritten by the matrix expression !> B := alpha * A * X + beta * B. !>
[in]	LDB	!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(N,1). !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.