Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 0.10
  • 10/21/2020
  • Public Content
Contents

?lauum

Computes the product
U
*
U
T
(
U
*
U
H
) or
L
T
*
L
 (
L
H
*
L
), where
U
 and
L
 are upper or lower triangular matrices (blocked algorithm).

Syntax

lapack_int
LAPACKE_slauum
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
float
*
a
,
lapack_int
lda
);
lapack_int
LAPACKE_dlauum
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
double
*
a
,
lapack_int
lda
);
lapack_int
LAPACKE_clauum
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
lapack_complex_float
*
a
,
lapack_int
lda
);
lapack_int
LAPACKE_zlauum
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
lapack_complex_double
*
a
,
lapack_int
lda
);
Include Files
  • mkl.h
Description
The routine
?lauum
 computes the product
U
*
U
T
 or
L
T
*
L
 for real flavors, and
U
*
U
H
 or
L
H
*
L
 for complex flavors. Here the triangular factor
U
 or
L
 is stored in the upper or lower triangular part of the array
a
.
If
uplo
 =
'U'
 or
'u'
, then the upper triangle of the result is stored, overwriting the factor
U
 in
A
.
If
uplo
 =
'L'
 or
'l'
, then the lower triangle of the result is stored, overwriting the factor
L
 in
A
.
This is the blocked form of the algorithm, calling BLAS Level 3 Routines.
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.
uplo
Specifies whether the triangular factor stored in the array
a
 is upper or lower triangular:
=
'U'
: Upper triangular
=
'L'
: Lower triangular
n
The order of the triangular factor
U
 or
L
.
n
≥
 0
.
a
Array of size
max(1,
lda
 *
n
)
.
On entry, the triangular factor
U
 or
L
.
lda
The leading dimension of the array
a
.
lda
≥
 max(1,
n
)
.
Output Parameters
a
On exit,
if
uplo
 =
'U'
, then the upper triangle of
a
 is overwritten with the upper triangle of the product
U
*
U
T
(
U
*
U
H
);
if
uplo
 =
'L'
, then the lower triangle of
a
 is overwritten with the lower triangle of the product
L
T
*
L
 (
L
H
*
L
).
Return Values
This function returns a value
info
.
If
info
 = 0
, the execution is successful.
If
info
 =
-k
, the
k
-th parameter had an illegal value.
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