Contents

# p?laset

Initializes the offdiagonal elements of a matrix to
alpha
and the diagonal elements to
beta
.

## Syntax

Include Files
• mkl_scalapack.h
Description
The
p?laset
function
initializes an
m
-by-
n
distributed matrix sub(
A
) denoting
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1) to
beta
on the diagonal and
alpha
on the offdiagonals.
Input Parameters
uplo
(global)
Specifies the part of the distributed matrix sub(
A
) to be set:
if
uplo
=
'U'
: upper triangular part; the strictly lower triangular part of sub(
A
) is not changed;
if
uplo
=
'L'
: lower triangular part; the strictly upper triangular part of sub(
A
) is not changed.
Otherwise: all of the matrix sub(
A
) is set.
m
(global)
The number of rows in the distributed matrix sub(
A
).
(
m
0)
.
n
(global)
The number of columns in the distributed matrix sub(
A
).
(
n
0)
.
alpha
(global).
The constant to which the offdiagonal elements are to be set.
beta
(global).
The constant to which the diagonal elements are to be set.
Output Parameters
a
(local).
Pointer into the local memory to an array of size
lld_a
*
LOCc
(
ja
+
n
-1)
.
This array contains the local pieces of the distributed matrix sub(
A
) to be set. On exit, the leading
m
-by-
n
matrix sub(
A
) is set as follows:
if
uplo
=
'U'
,
A
(
ia
+
i
-1,
ja
+
j
-1) =
alpha
, 1≤
i
j
-1
, 1≤
j
n
,
if
uplo
=
'L'
,
A
(
ia
+
i
-1,
ja
+
j
-1) =
alpha
,
j
+1≤
i
m
, 1≤
j
n
,
otherwise,
A
(
ia
+
i
-1,
ja
+
j
-1) =
alpha
, 1≤
i
m
, 1≤
j
n
,
ia
+
i
ja
+
j
, and, for all
uplo
,
A
(
ia
+
i
-1,
ja
+
i
-1) =
beta
, 1≤
i
≤min(
m
,
n
).
ia
,
ja
(global)
The column and row indices in the distributed matrix
A
indicating the first row and column of the matrix sub(
A
), respectively.
desca
(global and local)
Array of size
dlen_
. The array descriptor for the distributed matrix
A
.

#### Product and Performance Information

1

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