zlarfgp.f man page

zlarfgp.f —

Synopsis

Functions/Subroutines

subroutine zlarfgp (N, ALPHA, X, INCX, TAU)
ZLARFGP generates an elementary reflector (Householder matrix) with non-negatibe beta.

Function/Subroutine Documentation

subroutine zlarfgp (integerN, complex*16ALPHA, complex*16, dimension( * )X, integerINCX, complex*16TAU)

ZLARFGP generates an elementary reflector (Householder matrix) with non-negatibe beta.

Purpose:

ZLARFGP 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, beta is real and non-negative, 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.

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:

September 2012

Definition at line 105 of file zlarfgp.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK