SRC/slarfx.f(3) Library Functions Manual SRC/slarfx.f(3)

SRC/slarfx.f


subroutine slarfx (side, m, n, v, tau, c, ldc, work)
SLARFX applies an elementary reflector to a general rectangular matrix, with loop unrolling when the reflector has order ≤ 10.

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

Purpose:

!>
!> SLARFX 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 REAL array, dimension (M) if SIDE = 'L'
!>                                     or (N) if SIDE = 'R'
!>          The vector v in the representation of H.
!> 

TAU

!>          TAU is REAL
!>          The value tau in the representation of H.
!> 

C

!>          C is REAL 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 REAL 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 slarfx.f.

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