CLARFG
Purpose
CLARFG 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 .
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
| 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.
|