LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  zlarfg (N, ALPHA, X, INCX, TAU) 
ZLARFG generates an elementary reflector (Householder matrix). 
subroutine zlarfg  (  integer  N, 
complex*16  ALPHA,  
complex*16, dimension( * )  X,  
integer  INCX,  
complex*16  TAU  
) 
ZLARFG generates an elementary reflector (Householder matrix).
Download ZLARFG + dependencies [TGZ] [ZIP] [TXT]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 (n1)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 (n1)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(tau1) <= 1 .
[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+(N2)*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. 
Definition at line 107 of file zlarfg.f.