dlarfx()

subroutine dlarfx	(	character	side,
		integer	m,
		integer	n,
		double precision, dimension( * )	v,
		double precision	tau,
		double precision, dimension( ldc, * )	c,
		integer	ldc,
		double precision, dimension( * )	work )

DLARFX applies an elementary reflector to a general rectangular matrix, with loop unrolling when the reflector has order ≤ 10.

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Purpose:

!>
!> DLARFX applies a real elementary reflector H to a real m by n
!> matrix C, from either the left or the right. H is represented in the
!> form
!>
!>       H = I - tau * v * v**T
!>
!> where tau is a real scalar and v is a real vector.
!>
!> If tau = 0, then H is taken to be the unit matrix
!>
!> This version uses inline code if H has order < 11.
!> 

Parameters

[in]	SIDE	!> SIDE is CHARACTER*1 !> = 'L': form H * C !> = 'R': form C * H !>
[in]	M	!> M is INTEGER !> The number of rows of the matrix C. !>
[in]	N	!> N is INTEGER !> The number of columns of the matrix C. !>
[in]	V	!> V is DOUBLE PRECISION array, dimension (M) if SIDE = 'L' !> or (N) if SIDE = 'R' !> The vector v in the representation of H. !>
[in]	TAU	!> TAU is DOUBLE PRECISION !> The value tau in the representation of H. !>
[in,out]	C	!> C is DOUBLE PRECISION array, dimension (LDC,N) !> On entry, the m by n matrix C. !> On exit, C is overwritten by the matrix H * C if SIDE = 'L', !> or C * H if SIDE = 'R'. !>
[in]	LDC	!> LDC is INTEGER !> The leading dimension of the array C. LDC >= (1,M). !>
[out]	WORK	!> WORK is DOUBLE PRECISION array, dimension !> (N) if SIDE = 'L' !> or (M) if SIDE = 'R' !> WORK is not referenced if H has order < 11. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.