clarfgp3
Part of clarfgp.f(3).
Function/Subroutine Documentation
subroutine clarfgp (integer n, complex alpha, complex, dimension( * ) x, integer incx, complex tau)
CLARFGP generates an elementary reflector (Householder matrix) with non-negative beta.
Purpose:
!> !> CLARFGP 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, beta is real and non-negative, 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. !>
Parameters
N
!> N is INTEGER !> The order of the elementary reflector. !>
ALPHA
!> ALPHA is COMPLEX !> On entry, the value alpha. !> On exit, it is overwritten with the value beta. !>
X
!> X is COMPLEX array, dimension !> (1+(N-2)*abs(INCX)) !> On entry, the vector x. !> On exit, it is overwritten with the vector v. !>
INCX
!> INCX is INTEGER !> The increment between elements of X. INCX > 0. !>
TAU
!> TAU is COMPLEX !> The value tau. !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 103 of file clarfgp.f.
History
- Arch Linux 2026-11-01: the text shown here
- Debian 12 (Bookworm)
- Debian 11 (Bullseye)
- Debian 10 (Buster)
- Debian 9 (Stretch)
- Debian 8 (Jessie)
- Debian 7 (Wheezy)