sorgqr.f(3) LAPACK sorgqr.f(3)
subroutine sorgqr (M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
subroutine sorgqr (integerM, integerN, integerK, real, dimension( lda, * )A, integerLDA, real,
dimension( * )TAU, real, dimension( * )WORK, integerLWORK, integerINFO)
SORGQR generates an M-by-N real matrix Q with orthonormal columns,
which is defined as the first N columns of a product of K elementary
reflectors of order M
Q = H(1) H(2) . . . H(k)
as returned by SGEQRF.
M is INTEGER
The number of rows of the matrix Q. M >= 0.
N is INTEGER
The number of columns of the matrix Q. M >= N >= 0.
K is INTEGER
The number of elementary reflectors whose product defines the
matrix Q. N >= K >= 0.
A is REAL array, dimension (LDA,N)
On entry, the i-th column must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by SGEQRF in the first k columns of its array
On exit, the M-by-N matrix Q.
LDA is INTEGER
The first dimension of the array A. LDA >= max(1,M).
TAU is REAL array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by SGEQRF.
WORK is REAL 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,N).
For optimum performance LWORK >= N*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 sorgqr.f.
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Version 3.4.2 Tue Sep 25 2012 sorgqr.f(3)