table of contents
zlarfg.f(3) | LAPACK | zlarfg.f(3) |
NAME¶
zlarfg.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine zlarfg (N, ALPHA, X, INCX, TAU)
ZLARFG generates an elementary reflector (Householder matrix).
Function/Subroutine Documentation¶
subroutine zlarfg (integer N, complex*16 ALPHA, complex*16, dimension( * ) X, integer INCX, complex*16 TAU)¶
ZLARFG generates an elementary reflector (Householder matrix).
Purpose:
ZLARFG generates a complex elementary reflector H of order n, such
that
H**H * ( alpha ) = ( beta ), H**H * H = I.
( x ) ( 0 )
where alpha and beta are scalars, with beta real, and x is an
(n-1)-element complex vector. H is represented in the form
H = I - tau * ( 1 ) * ( 1 v**H ) ,
( v )
where tau is a complex scalar and v is a complex (n-1)-element
vector. Note that H is not hermitian.
If the elements of x are all zero and alpha is real, then tau = 0
and H is taken to be the unit matrix.
Otherwise 1 <= real(tau) <= 2 and abs(tau-1) <= 1 .
Parameters:
N
N is INTEGER
The order of the elementary reflector.
ALPHA
ALPHA is COMPLEX*16
On entry, the value alpha.
On exit, it is overwritten with the value beta.
X
X is COMPLEX*16 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 COMPLEX*16
The value tau.
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2017
Definition at line 108 of file zlarfg.f.
Author¶
Generated automatically by Doxygen for LAPACK from the source code.
Tue Nov 14 2017 | Version 3.8.0 |