SRC/cupgtr.f(3) | Library Functions Manual | SRC/cupgtr.f(3) |
NAME
SRC/cupgtr.f
SYNOPSIS
Functions/Subroutines
subroutine cupgtr (uplo, n, ap, tau, q, ldq, work, info)
CUPGTR
Function/Subroutine Documentation
subroutine cupgtr (character uplo, integer n, complex, dimension( * ) ap, complex, dimension( * ) tau, complex, dimension( ldq, * ) q, integer ldq, complex, dimension( * ) work, integer info)
CUPGTR
Purpose:
CUPGTR 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 CHPTRD 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 CHPTRD; = 'L': Lower triangular packed storage used in previous call to CHPTRD.
N
N is INTEGER The order of the matrix Q. N >= 0.
AP
AP is COMPLEX array, dimension (N*(N+1)/2) The vectors which define the elementary reflectors, as returned by CHPTRD.
TAU
TAU is COMPLEX array, dimension (N-1) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CHPTRD.
Q
Q is COMPLEX 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 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 cupgtr.f.
Author
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Version 3.12.0 | LAPACK |