zupgtr.f3
Usage
Functions/Subroutines
subroutine zupgtr (uplo, n, ap, tau, q, ldq, work, info)
ZUPGTR
Function/Subroutine Documentation
subroutine zupgtr (character uplo, integer n, complex*16, dimension( * ) ap, complex*16, dimension( * ) tau, complex*16, dimension( ldq, * ) q, integer ldq, complex*16, dimension( * ) work, integer info)
ZUPGTR
Purpose:
!> !> ZUPGTR generates a complex unitary matrix Q which is defined as the !> product of n-1 elementary reflectors H(i) of order n, as returned by !> ZHPTRD using packed storage: !> !> if UPLO = 'U', Q = H(n-1) . . . H(2) H(1), !> !> if UPLO = 'L', Q = H(1) H(2) . . . H(n-1). !>
Parameters
UPLO
!> UPLO is CHARACTER*1 !> = 'U': Upper triangular packed storage used in previous !> call to ZHPTRD; !> = 'L': Lower triangular packed storage used in previous !> call to ZHPTRD. !>
N
!> N is INTEGER !> The order of the matrix Q. N >= 0. !>
AP
!> AP is COMPLEX*16 array, dimension (N*(N+1)/2) !> The vectors which define the elementary reflectors, as !> returned by ZHPTRD. !>
TAU
!> TAU is COMPLEX*16 array, dimension (N-1) !> TAU(i) must contain the scalar factor of the elementary !> reflector H(i), as returned by ZHPTRD. !>
Q
!> Q is COMPLEX*16 array, dimension (LDQ,N) !> The N-by-N unitary matrix Q. !>
LDQ
!> LDQ is INTEGER !> The leading dimension of the array Q. LDQ >= max(1,N). !>
WORK
!> WORK is COMPLEX*16 array, dimension (N-1) !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 113 of file zupgtr.f.
Releases
4 releases since Debian 7 (Wheezy); the text changed 3 times.