Developer Reference

Contents

p?lapv2

Applies a permutation to an
m
-by-
n
distributed matrix.

Syntax

void pslapv2
(
const
char*
direc
,
const
char*
rowcol
,
const
MKL_INT*
m
,
const
MKL_INT*
n
,
float*
a
,
const
MKL_INT*
ia
,
const
MKL_INT*
ja
,
const
MKL_INT*
desca
,
const
MKL_INT*
ipiv
,
const
MKL_INT*
ip
,
const
MKL_INT*
jp
,
const
MKL_INT*
descip
);
void pdlapv2
(
const
char*
direc
,
const
char*
rowcol
,
const
MKL_INT*
m
,
const
MKL_INT*
n
,
double*
a
,
const
MKL_INT*
ia
,
const
MKL_INT*
ja
,
const
MKL_INT*
desca
,
const
MKL_INT*
ipiv
,
const
MKL_INT*
ip
,
const
MKL_INT*
jp
,
const
MKL_INT*
descip
);
void pclapv2
(
const
char*
direc
,
const
char*
rowcol
,
const
MKL_INT*
m
,
const
MKL_INT*
n
,
MKL_Complex8*
a
,
const
MKL_INT*
ia
,
const
MKL_INT*
ja
,
const
MKL_INT*
desca
,
const
MKL_INT*
ipiv
,
const
MKL_INT*
ip
,
const
MKL_INT*
jp
,
const
MKL_INT*
descip
);
void pzlapv2
(
const
char*
direc
,
const
char*
rowcol
,
const
MKL_INT*
m
,
const
MKL_INT*
n
,
MKL_Complex16*
a
,
const
MKL_INT*
ia
,
const
MKL_INT*
ja
,
const
MKL_INT*
desca
,
const
MKL_INT*
ipiv
,
const
MKL_INT*
ip
,
const
MKL_INT*
jp
,
const
MKL_INT*
descip
);
Include Files
  • mkl_scalapack.h
Description
p?lapv2
applies either
P
(permutation matrix indicated by
ipiv
) or inv(
P
) to an
m
-by-
n
distributed matrix sub(
A
) denoting
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1), resulting in row or column pivoting. The pivot vector should be aligned with the distributed matrix
A
. For pivoting the rows of sub(
A
),
ipiv
should be distributed along a process column and replicated over all process rows. Similarly,
ipiv
should be distributed along a process row and replicated over all process columns for column pivoting.
Input Parameters
direc
(global)
Specifies in which order the permutation is applied:
= 'F' (Forward) Applies pivots Forward from top of matrix. Computes
P
* sub(
A
);
= 'B' (Backward) Applies pivots Backward from bottom of matrix. Computes inv(
P
) * sub(
A
).
rowcol
(global)
Specifies if the rows or columns are to be permuted:
= 'R' Rows will be permuted,
= 'C' Columns will be permuted.
m
(global)
The number of rows to be operated on, i.e. the number of rows of the distributed submatrix sub(
A
).
m
>= 0.
n
(global)
The number of columns to be operated on, i.e. the number of columns of the distributed submatrix sub(
A
).
n
>= 0.
a
Pointer into local memory to an array of size
lld_a
*
LOCc
(
ja
+
n
-1)
.
On entry, this local array contains the local pieces of the distributed matrix sub(
A
) to which the row or columns interchanges will be applied.
ia
(global)
The row index in the global array
a
indicating the first row of sub(
A
).
ja
(global)
The column index in the global array
a
indicating the first column of sub(
A
).
desca
(global and local)
Array of size
dlen_
.
The array descriptor for the distributed matrix
A
.
ipiv
Array, size >= LOCr(
m_a
)+
mb_a
if
rowcol
= 'R', LOCc(
n_a
)+
nb_a
otherwise.
It contains the pivoting information.
ipiv
[
i
- 1]
is the global row (column), local row (column)
i
was swapped with. The last piece of the array of size
mb_a
or
nb_a
is used as workspace.
ipiv
is tied to the distributed matrix
A
.
ip
(global)
The global row index of
ipiv
, which points to the beginning of the submatrix on which to operate.
jp
(global)
The global column index of
ipiv
, which points to the beginning of the submatrix on which to operate.
descip
(global and local)
Array of size 8.
The array descriptor for the distributed matrix
ipiv
.
Output Parameters
a
On exit, this array contains the local pieces of the permuted distributed matrix.

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