clarfg.f man page

clarfg.f —

Synopsis

Functions/Subroutines

subroutine clarfg (N, ALPHA, X, INCX, TAU)
CLARFG generates an elementary reflector (Householder matrix).

Function/Subroutine Documentation

subroutine clarfg (integer N, complex ALPHA, complex, dimension( * ) X, integer INCX, complex TAU)

CLARFG generates an elementary reflector (Householder matrix).  

Purpose:

 CLARFG 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
          On entry, the value alpha.
          On exit, it is overwritten with the value beta.

X

          X is COMPLEX 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
          The value tau.
Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 108 of file clarfg.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page clarfg(3) is an alias of clarfg.f(3).

Sat Jun 24 2017 Version 3.7.1 LAPACK