cungrq.f(3) LAPACK cungrq.f(3)
subroutine cungrq (M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
subroutine cungrq (integerM, integerN, integerK, complex, dimension( lda, * )A, integerLDA,
complex, dimension( * )TAU, complex, dimension( * )WORK, integerLWORK, integerINFO)
CUNGRQ generates an M-by-N complex matrix Q with orthonormal rows,
which is defined as the last M rows of a product of K elementary
reflectors of order N
Q = H(1)**H H(2)**H . . . H(k)**H
as returned by CGERQF.
M is INTEGER
The number of rows of the matrix Q. M >= 0.
N is INTEGER
The number of columns of the matrix Q. N >= M.
K is INTEGER
The number of elementary reflectors whose product defines the
matrix Q. M >= K >= 0.
A is COMPLEX array, dimension (LDA,N)
On entry, the (m-k+i)-th row must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by CGERQF in the last k rows of its array argument
On exit, the M-by-N matrix Q.
LDA is INTEGER
The first dimension of the array A. LDA >= max(1,M).
TAU is COMPLEX array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by CGERQF.
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 >= max(1,M).
For optimum performance LWORK >= M*NB, where NB is the
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 has an illegal value
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
Definition at line 129 of file cungrq.f.
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 cungrq.f(3)