Developer Reference

  • 2021.1
  • 12/04/2020
  • 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

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.