redhat man page for clarfg

CLARFG(l)								 )								 CLARFG(l)

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( * )

PURPOSE
       CLARFG generates a complex elementary reflector H of order n, such that H' * ( alpha ) = ( beta ), 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' ) ,
			   ( 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.

LAPACK version 3.0						   15 June 2000 							 CLARFG(l)