Visible to Intel only — GUID: GUID-F76382EC-8D6A-44B0-9AD9-978454ECEE82
Visible to Intel only — GUID: GUID-F76382EC-8D6A-44B0-9AD9-978454ECEE82
?org2l/?ung2l
Generates all or part of the orthogonal/unitary matrix Q from a QL factorization determined by ?geqlf (unblocked algorithm).
Syntax
call sorg2l( m, n, k, a, lda, tau, work, info )
call dorg2l( m, n, k, a, lda, tau, work, info )
call cung2l( m, n, k, a, lda, tau, work, info )
call zung2l( m, n, k, a, lda, tau, work, info )
Include Files
- mkl.fi
Description
The routine ?org2l/?ung2l generates an m-by-n real/complex matrix Q with orthonormal columns, which is defined as the last n columns of a product of k elementary reflectors of order m:
Q = H(k)*...*H(2)*H(1) as returned by ?geqlf.
Input Parameters
- m
-
INTEGER. The number of rows of the matrix Q. m≥ 0.
- n
-
INTEGER. The number of columns of the matrix Q. m≥n≥ 0.
- k
-
INTEGER. The number of elementary reflectors whose product defines the matrix Q. n≥k≥ 0.
- a
-
REAL for sorg2l
DOUBLE PRECISION for dorg2l
COMPLEX for cung2l
DOUBLE COMPLEX for zung2l.
Array, DIMENSION (lda,n).
On entry, the (n-k+i)-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,..., k, as returned by ?geqlf in the last k columns of its array argument A.
- lda
-
INTEGER. The leading dimension of the array a. lda≥ max(1,m).
- tau
-
REAL for sorg2l
DOUBLE PRECISION for dorg2l
COMPLEX for cung2l
DOUBLE COMPLEX for zung2l.
Array, DIMENSION (k).
tau(i) must contain the scalar factor of the elementary reflector H(i), as returned by ?geqlf.
- work
-
REAL for sorg2l
DOUBLE PRECISION for dorg2l
COMPLEX for cung2l
DOUBLE COMPLEX for zung2l.
Workspace array, DIMENSION (n).
Output Parameters
- a
-
On exit, the m-by-n matrix Q.
- info
-
INTEGER.
= 0: successful exit
< 0: if info = -i, the i-th argument has an illegal value