Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 0.9
  • 09/09/2020
  • Public Content
Contents

?getf2

Computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

Syntax

lapack_int
LAPACKE_sgetf2
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
float
*
a
,
lapack_int
lda
,
lapack_int
*
ipiv
);
lapack_int
LAPACKE_dgetf2
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
double
*
a
,
lapack_int
lda
,
lapack_int
*
ipiv
);
lapack_int
LAPACKE_cgetf2
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
lapack_complex_float
*
a
,
lapack_int
lda
,
lapack_int
*
ipiv
);
lapack_int
LAPACKE_zgetf2
(
int
matrix_layout
,
lapack_int
m
,
lapack_int
n
,
lapack_complex_double
*
a
,
lapack_int
lda
,
lapack_int
*
ipiv
);
Include Files
  • mkl.h
Description
The routine computes the
LU
 factorization of a general
m
-by-
n
 matrix
A
 using partial pivoting with row interchanges. The factorization has the form
A
 =
P
*
L
*
U
where
p
 is a permutation matrix,
L
 is lower triangular with unit diagonal elements (lower trapezoidal if
m
 >
n
) and
U
 is upper triangular (upper trapezoidal if
m
 <
n
).
Input Parameters
A
<datatype>
 placeholder, if present, is used for the C interface data types in the C interface section above. See C Interface Conventions for the C interface principal conventions and type definitions.
m
The number of rows in the matrix
A
 (
m
≥
 0
).
n
The number of columns in
A
 (
n
≥
 0
).
a
Array, size at least
max(1,
lda
*
n
)
 for column major and
max(1,
lda
*
m
)
 for row major layout. Array
a
 contains the
m
-by-
n
 matrix
A
.
lda
The leading dimension of
a
; at least max(1,
m
)
for column major layout and max(1,
n
) for row major layout
.
Output Parameters
a
Overwritten by
L
 and
U
. The unit diagonal elements of
L
 are not stored.
ipiv
Array, size at least
max(1,min(
m
,
n
))
.
The pivot indices: for
1 ≤ i ≤
n
, row
i
 was interchanged with row
ipiv
(
i
).
Return Values
This function returns a value
info
.
If
info
 =
-i
, the
i
-th parameter had an illegal value.
If
info
 =
i
 >0
,
u
i
i
 is 0. The factorization has been completed, but
U
 is exactly singular. Division by 0 will occur if you use the factor
U
 for solving a system of linear equations.
If
info
 = -1011
, memory allocation error occurred.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804