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NAME
     clarfg - generate a complex elementary reflector H of  order
     n, such that   H' * ( alpha ) = ( beta ), H' * H = I

SYNOPSIS
     SUBROUTINE CLARFG( N, ALPHA, X, INCX, TAU )

     INTEGER INCX, N

     COMPLEX ALPHA, TAU

     COMPLEX X( * )



     #include <sunperf.h>

     void clarfg(int n, complex *calpha, complex *cx,  int  incx,
               complex *tau) ;

PURPOSE
     CLARFG generates a complex elementary reflector H  of  order
     n, such that
                (   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' ) ,
                         ( 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
     N         (input) INTEGER
               The order of the elementary reflector.

     ALPHA     (input/output) COMPLEX
               On  entry,  the  value  alpha.   On  exit,  it  is
               overwritten with the value beta.

     X         (input/output) COMPLEX array, dimension
               (1+(N-2)*abs(INCX)) On entry, the  vector  x.   On
               exit, it is overwritten with the vector v.

     INCX      (input) INTEGER
               The increment between elements of X. INCX > 0.

     TAU       (output) COMPLEX
               The value tau.

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