dlarfx.f man page

dlarfx.f —

Synopsis

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 (characterSIDE, integerM, integerN, double precision, dimension( * )V, double precisionTAU, double precision, dimension( ldc, * )C, integerLDC, 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. LDA >= (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.

Date:

September 2012

Definition at line 121 of file dlarfx.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dlarfx(3) is an alias of dlarfx.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK