cungtr.f(3) LAPACK cungtr.f(3)NAME
subroutine cungtr (UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)
subroutine cungtr (characterUPLO, integerN, complex, dimension( lda, * )A,
integerLDA, complex, dimension( * )TAU, complex, dimension( * )WORK,
CUNGTR generates a complex unitary matrix Q which is defined as the
product of n-1 elementary reflectors of order N, as returned by
if UPLO = 'U', Q = H(n-1) . . . H(2)H(1),
if UPLO = 'L', Q = H(1)H(2) . . . H(n-1).
UPLO is CHARACTER*1
= 'U': Upper triangle of A contains elementary reflectors
= 'L': Lower triangle of A contains elementary reflectors
N is INTEGER
The order of the matrix Q. N >= 0.
A is COMPLEX array, dimension (LDA,N)
On entry, the vectors which define the elementary reflectors,
as returned by CHETRD.
On exit, the N-by-N unitary matrix Q.
LDA is INTEGER
The leading dimension of the array A. LDA >= N.
TAU is COMPLEX array, dimension (N-1)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by CHETRD.
WORK is COMPLEX array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK is INTEGER
The dimension of the array WORK. LWORK >= N-1.
For optimum performance LWORK >= (N-1)*NB, where NB is
the optimal blocksize.
If LWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
Definition at line 124 of file cungtr.f.
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 cungtr.f(3)