dlarfx.f3
Usage
Functions/Subroutines
subroutine dlarfx (side, m, n, v, tau, c, ldc, work)
DLARFX applies an elementary reflector to a general rectangular matrix, with loop unrolling when the reflector has order ≤ 10.
Function/Subroutine Documentation
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.
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
SIDE
!> SIDE is CHARACTER*1 !> = 'L': form H * C !> = 'R': form C * H !>
M
!> M is INTEGER !> The number of rows of the matrix C. !>
N
!> N is INTEGER !> The number of columns of the matrix C. !>
V
!> V is DOUBLE PRECISION array, dimension (M) if SIDE = 'L' !> or (N) if SIDE = 'R' !> The vector v in the representation of H. !>
TAU
!> TAU is DOUBLE PRECISION !> The value tau in the representation of H. !>
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'. !>
LDC
!> LDC is INTEGER !> The leading dimension of the array C. LDC >= (1,M). !>
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.
Definition at line 119 of file dlarfx.f.
Releases
4 releases since Debian 7 (Wheezy); the text changed 3 times.