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slarfg.f(3) LAPACK slarfg.f(3)NAME
slarfg.f -
SYNOPSIS
Functions/Subroutines
subroutine slarfg (N, ALPHA, X, INCX, TAU)
SLARFG generates an elementary reflector (Householder matrix).
Function/Subroutine Documentation
subroutine slarfg (integerN, realALPHA, real, dimension( * )X, integerINCX, realTAU)
SLARFG generates an elementary reflector (Householder matrix).
Purpose:
SLARFG generates a real elementary reflector H of order n, such
that
H * ( alpha ) = ( beta ), H**T * H = I.
( x ) ( 0 )
where alpha and beta are scalars, and x is an (n-1)-element real
vector. H is represented in the form
H = I - tau * ( 1 ) * ( 1 v**T ) ,
( v )
where tau is a real scalar and v is a real (n-1)-element
vector.
If the elements of x are all zero, then tau = 0 and H is taken to be
the unit matrix.
Otherwise 1 <= tau <= 2.
Parameters:
N
N is INTEGER
The order of the elementary reflector.
ALPHA
ALPHA is REAL
On entry, the value alpha.
On exit, it is overwritten with the value beta.
X
X is REAL array, dimension
(1+(N-2)*abs(INCX))
On entry, the vector x.
On exit, it is overwritten with the vector v.
INCX
INCX is INTEGER
The increment between elements of X. INCX > 0.
TAU
TAU is REAL
The value tau.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
September 2012
Definition at line 107 of file slarfg.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 slarfg.f(3)