Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

Contents

p?lauum

Computes the product
U
*
U
'
or
L
'*
L
, where
U
 and
L
 are upper or lower triangular matrices.

Syntax

void
pslauum
(
char
*uplo
,
MKL_INT
*n
,
float
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
);
void
pdlauum
(
char
*uplo
,
MKL_INT
*n
,
double
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
);
void
pclauum
(
char
*uplo
,
MKL_INT
*n
,
MKL_Complex8
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
);
void
pzlauum
(
char
*uplo
,
MKL_INT
*n
,
MKL_Complex16
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
);
Include Files
  • mkl_scalapack.h
Description
The
p?lauum
function
computes the product
U*U
' or
L'*L
, where the triangular factor
U
 or
L
 is stored in the upper or lower triangular part of the matrix sub
(
A
)=
A
(
ia
:
ia
+
n
-1,
ja
:
ja
+
n
-1)
.
If
uplo
 =
'U'
 or
'u'
, then the upper triangle of the result is stored, overwriting the factor
U
 in sub(
A
). If
uplo
 =
'L'
 or
'l'
, then the lower triangle of the result is stored, overwriting the factor
L
 in sub(
A
).
This is the blocked form of the algorithm, calling Level 3 PBLAS.
Input Parameters
uplo
(global)
Specifies whether the triangular factor stored in the matrix sub(
A
) is upper or lower triangular:
=
'U'
: upper triangular
=
'L'
: lower triangular.
n
(global)
The number of rows and columns to be operated on, that is, the order of the triangular factor
U
 or
L
.
n
≥
 0
.
a
(local)
Pointer into the local memory to an array of size
lld_a
 *
LOCc
(
ja
+
n
-1)
. On entry, the local pieces of the triangular factor
U
 or
L
.
ia
(global)
The row index in the global matrix
A
 indicating the first row of sub(
A
).
ja
(global)
The column index in the global matrix
A
 indicating the first column of sub(
A
).
desca
(global and local) array of size
dlen_
. The array descriptor for the distributed matrix
A
.
Output Parameters
a
(local)
On exit, if
uplo
 =
'U'
, the upper triangle of the distributed matrix sub(
A
) is overwritten with the upper triangle of the product
U*U
' ; if
uplo
 =
'L'
, the lower triangle of sub(
A
) is overwritten with the lower triangle of the product
L
'*
L
.

Product and Performance Information

1

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