cungl23lapack
Generates an m-by-n complex matrix q with orthonormal rows,
Usage
- SUBROUTINE CUNGL2(
-
M, N, K, A, LDA, TAU, WORK, INFO )
- INTEGER
-
INFO, K, LDA, M, N
- COMPLEX
-
A( LDA, * ), TAU( * ), WORK( * )
Purpose
CUNGL2 generates an m-by-n complex matrix Q with orthonormal rows, which is defined as the first m rows of a product of k elementary reflectors of order n
Q = H(k)' . . . H(2)' H(1)'
as returned by CGELQF.
Arguments
- M (input) INTEGER
-
The number of rows of the matrix Q. M >= 0.
- N (input) INTEGER
-
The number of columns of the matrix Q. N >= M.
- K (input) INTEGER
-
The number of elementary reflectors whose product defines the matrix Q. M >= K >= 0.
- A (input/output) COMPLEX array, dimension (LDA,N)
-
On entry, the i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGELQF in the first k rows of its array argument A. On exit, the m by n matrix Q.
- LDA (input) INTEGER
-
The first dimension of the array A. LDA >= max(1,M).
- TAU (input) COMPLEX array, dimension (K)
-
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGELQF.
- WORK (workspace) COMPLEX array, dimension (M)
- INFO (output) INTEGER
-
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value