slarz.f man page

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 (characterSIDE, integerM, integerN, integerL, real, dimension( * )V, integerINCV, realTAU, real, dimension( ldc, * )C, integerLDC, 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.

Date:

September 2012

Contributors:

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

Further Details:

Definition at line 146 of file slarz.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK