Contents

# p?laqsy

Scales a symmetric/Hermitian matrix, using scaling factors computed by
p?poequ
.

## Syntax

Include Files
• mkl_scalapack.h
Description
The
p?laqsy
function
equilibrates a symmetric distributed matrix sub(
A
) =
A
(
ia
:
ia
+
n
-1,
ja
:
ja
+
n
-1)
using the scaling factors in the vectors
sr
and
sc
. The scaling factors are computed by
p?poequ
.
Input Parameters
uplo
(global) Specifies the upper or lower triangular part of the symmetric distributed matrix
sub(
A
)
is to be referenced:
=
'U'
: Upper triangular part;
=
'L'
: Lower triangular part.
n
(global)
The order of the distributed matrix sub(
A
).
n
0
.
a
(local).
Pointer into the local memory to an array of size
lld_a
*
LOCc
(
ja
+
n
-1)
.
On entry, this array contains the local pieces of the distributed matrix sub(
A
). On entry, the local pieces of the distributed symmetric matrix sub(
A
).
If
uplo
=
'U'
n
-by-
n
upper triangular part of sub(
A
) contains the upper triangular part of the matrix, and the strictly lower triangular part of sub(
A
) is not referenced.
If
uplo
=
'L'
n
-by-
n
lower triangular part of sub(
A
) contains the lower triangular part of the matrix, and the strictly upper triangular part of sub(
A
) is not referenced.
ia
,
ja
(global)
The row and column indices in the global matrix
A
indicating the first row and the first column of the matrix sub(
A
), respectively.
desca
(global and local) array of size
dlen_
. The array descriptor for the distributed matrix A.
sr
(local)
Array of size
LOCr
(
m_a
). The scale factors for
the matrix
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1).
sr
is aligned with the distributed matrix
A
, and replicated across every process column.
sr
is tied to the distributed matrix
A
.
sc
(local)
Array of size
LOCc
(
m_a
). The scale factors for
the matrix
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1).
sc
is aligned with the distributed matrix
A
, and replicated across every process column.
sc
is tied to the distributed matrix
A
.
scond
(global).
Ratio of the smallest
sr
[
i
]
(respectively
sc
[
j
]
) to the largest
sr
[
i
]
(respectively
sc
[
j
]
), with
ia
-1 ≤
i
<
ia
+
n
-1 and
ja
-1 ≤
j
<
ja
+
n
-1
.
amax
(global).
Absolute value of largest distributed submatrix entry.
Output Parameters
a
On exit,
if
equed
=
'Y'
, the equilibrated matrix:
diag(
sr
ia
, ...,
sr
ia
+
n
-1
) * sub(
A
) * diag(
sc
ja
, ...,
sc
ja
+
n
-1
)
.
equed
(global).
Specifies whether or not equilibration was done.
=
'N'
: No equilibration.
=
'Y'
: Equilibration was done, that is, sub(
A
) has been replaced by:
diag(
sr
ia
, ...,
sr
ia
+
n
-1
) * sub(
A
) * diag(
sc
ja
, ...,
sc
ja
+
n
-1
)
.

#### 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