zlarfg (l)  Linux Man Pages
zlarfg: generates a complex elementary reflector H of order n, such that Haq * ( alpha ) = ( beta ), Haq * H = I
NAME
ZLARFG  generates a complex elementary reflector H of order n, such that Haq * ( alpha ) = ( beta ), Haq * H = ISYNOPSIS
 SUBROUTINE ZLARFG(
 N, ALPHA, X, INCX, TAU )
 INTEGER INCX, N
 COMPLEX*16 ALPHA, TAU
 COMPLEX*16 X( * )
PURPOSE
ZLARFG generates a complex elementary reflector H of order n, such thatwhere alpha and beta are scalars, with beta real, and x is an (n1)element complex vector. H is represented in the form
H
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 .
ARGUMENTS
 N (input) INTEGER
 The order of the elementary reflector.
 ALPHA (input/output) COMPLEX*16
 On entry, the value alpha. On exit, it is overwritten with the value beta.
 X (input/output) COMPLEX*16 array, dimension
 (1+(N2)*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*16

The value tau.