?geqlf
?geqlf
Computes the QL factorization of a general m-by-n matrix.
Syntax
lapack_int
LAPACKE_sgelqf
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
float
*
a
,
lapack_int
lda
,
float
*
tau
);
lapack_int
LAPACKE_dgelqf
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
double
*
a
,
lapack_int
lda
,
double
*
tau
);
lapack_int
LAPACKE_cgelqf
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
lapack_complex_float
*
a
,
lapack_int
lda
,
lapack_complex_float
*
tau
);
lapack_int
LAPACKE_zgelqf
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
lapack_complex_double
*
a
,
lapack_int
lda
,
lapack_complex_double
*
tau
);
Include Files
- mkl.h
Description
The routine forms the
QL
factorization of a general m
-by-n
matrix A
(see Orthogonal Factorizations). No pivoting is performed.The routine does not form the matrix
Q
explicitly. Instead, Q
is represented as a product of min(m
, n
) elementary reflectors. Routines are provided to work with Q
in this representation. This routine supports the Progress Routine feature. See Progress Function for details.
Input Parameters
- matrix_layout
- Specifies whether matrix storage layout is row major (LAPACK_ROW_MAJOR) or column major (LAPACK_COL_MAJOR).
- m
- The number of rows in the matrixA().m≥0
- n
- The number of columns inA().n≥0
- a
- Arrayaof size max(1,contains the matrixlda*n) for column major layout and max(1,lda*m) for row major layoutA.
- lda
- The leading dimension ofa; at least max(1,m)for column major layout and max(1,.n) for row major layout
Output Parameters
- a
- Overwritten on exit by the factorization data as follows:if, the lower triangle of the subarraym≥na(m-n+1:m, 1:n) contains then-by-nlower triangular matrixL; if, the elements on and below the (m≤nn-m)-th superdiagonal contain them-by-nlower trapezoidal matrixL; in both cases, the remaining elements, with the arraytau, represent the orthogonal/unitary matrixQas a product of elementary reflectors.
- tau
- Array, size at least max(1, min(m,n)). Contains scalar factors of the elementary reflectors for the matrixQ(see Orthogonal Factorizations).
Return Values
This function returns a value
info
.If , the execution is successful.
info
=0If , the
info
= -i
i
-th parameter had an illegal value.