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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlarf.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlarf.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlarf.f

SYNOPSIS

Functions/Subroutines


subroutine DLARF (side, m, n, v, incv, tau, c, ldc, work)
DLARF applies an elementary reflector to a general rectangular matrix.

Function/Subroutine Documentation

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

DLARF applies an elementary reflector to a general rectangular matrix.

Purpose:

!>
!> DLARF 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.
!>

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
!>                     (1 + (M-1)*abs(INCV)) if SIDE = 'L'
!>                  or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
!>          The vector v in the representation of H. V is not used if
!>          TAU = 0.
!>

INCV

!>          INCV is INTEGER
!>          The increment between elements of v. INCV <> 0.
!>

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 >= max(1,M).
!>

WORK

!>          WORK is DOUBLE PRECISION array, dimension
!>                         (N) if SIDE = 'L'
!>                      or (M) if SIDE = 'R'
!>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 123 of file dlarf.f.

Author

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Version 3.12.0 LAPACK