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

NAME

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

SYNOPSIS

Functions/Subroutines


subroutine SLARZ (side, m, n, l, v, incv, tau, c, ldc, work)
SLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.

Function/Subroutine Documentation

subroutine SLARZ (character side, integer m, integer n, integer l, real, dimension( * ) v, integer incv, real tau, real, dimension( ldc, * ) c, integer ldc, real, dimension( * ) work)

SLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.

Purpose:

!>
!> SLARZ 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.
!>
!>
!> H is a product of k elementary reflectors as returned by STZRZF.
!> 

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.
!> 

L

!>          L is INTEGER
!>          The number of entries of the vector V containing
!>          the meaningful part of the Householder vectors.
!>          If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
!> 

V

!>          V is REAL array, dimension (1+(L-1)*abs(INCV))
!>          The vector v in the representation of H as returned by
!>          STZRZF. V is not used if TAU = 0.
!> 

INCV

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

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 >= max(1,M).
!> 

WORK

!>          WORK is REAL 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.

Contributors:

A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA

Further Details:

!> 

Definition at line 144 of file slarz.f.

Author

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Version 3.12.0 LAPACK