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zlarfg examples
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Man Page Details
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 Online html documentation available at 
            http://www.netlib.org/lapack/explore-html/ 

 Definition:
 ===========

       SUBROUTINE ZLARFG( N, ALPHA, X, INCX, TAU )
 
       .. Scalar Arguments ..
       INTEGER            INCX, N
       COMPLEX*16         ALPHA, TAU
       ..
       .. Array Arguments ..
       COMPLEX*16         X( * )
       ..
  

 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 .

 Arguments:
 ==========

  [in] N

          N is INTEGER
          The order of the elementary reflector.

  [in,out] ALPHA

          ALPHA is COMPLEX*16
          On entry, the value alpha.
          On exit, it is overwritten with the value beta.

  [in,out] 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.

  [in] INCX

          INCX is INTEGER
          The increment between elements of X. INCX > 0.

  [out] TAU

          TAU is COMPLEX*16
          The value tau.

 Authors:
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  Univ. of Tennessee 
  Univ. of California Berkeley 
  Univ. of Colorado Denver 
  NAG Ltd. 

 November 2011

