Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content
Contents

p?rot

Applies a planar rotation to two distributed vectors.

Syntax

void psrot
(
MKL_INT*
n
,
float*
x
,
MKL_INT*
ix
,
MKL_INT*
jx
,
MKL_INT*
descx
,
MKL_INT*
incx
,
float*
y
,
MKL_INT*
iy
,
MKL_INT*
jy
,
MKL_INT*
descy
,
MKL_INT*
incy
,
float*
cs
,
float*
sn
,
float*
work
,
MKL_INT*
lwork
,
MKL_INT*
info
);
void pdrot
(
MKL_INT*
n
,
double*
x
,
MKL_INT*
ix
,
MKL_INT*
jx
,
MKL_INT*
descx
,
MKL_INT*
incx
,
double*
y
,
MKL_INT*
iy
,
MKL_INT*
jy
,
MKL_INT*
descy
,
MKL_INT*
incy
,
double*
cs
,
double*
sn
,
double*
work
,
MKL_INT*
lwork
,
MKL_INT*
info
);
Include Files
  • mkl_scalapack.h
Description
p?rot
 applies a planar rotation defined by
cs
 and
sn
 to the two distributed vectors sub(
x
) and sub(
y
).
Input Parameters
n
(global )
The number of elements to operate on when applying the planar rotation to
x
 and
y
 (
n
≥
0).
x
(local) array of size ( (
jx
-1)*
m_x
 +
ix
 + (
n
 - 1 )*abs(
incx
 ) )
This array contains the entries of the distributed vector sub(
x
 ).
ix
(global )
The global row index of the submatrix of the distributed matrix
x
 to operate on. If
incx
 = 1, then it is required that
ix
 =
iy
. 1
≤
ix
≤
m_x
.
jx
(global )
The global column index of the submatrix of the distributed matrix
x
 to operate on. If
incx
 =
m_x
, then it is required that
jx
 =
jy
. 1
≤
ix
≤
n_x
.
descx
(global and local) array of size 9
The array descriptor of the distributed matrix
x
.
incx
(global )
The global increment for the elements of
x
. Only two values of
incx
 are supported in this version, namely 1 and
m_x
. Moreover, it must hold that
incx
 =
m_x
 if
incy
 =
m_y
 and that
incx
 = 1 if
incy
 = 1.
y
(local) array of size ( (
jy
-1)*
m_y
 +
iy
 + (
n
 - 1 )*abs(
incy
 ) )
This array contains the entries of the distributed vector sub(
y
 ).
iy
(global )
The global row index of the submatrix of the distributed matrix
y
 to operate on. If
incy
 = 1, then it is required that
iy
 =
ix
. 1
≤
iy
≤
m_y
.
jy
(global )
The global column index of the submatrix of the distributed matrix
y
 to operate on. If
incy
 =
m_x
, then it is required that
jy
 =
jx
. 1
≤
jy
≤
m_y
.
descy
(global and local) array of size 9
The array descriptor of the distributed matrix
y
.
incy
(global )
The global increment for the elements of
y
. Only two values of
incy
 are supported in this version, namely 1 and
m_y
. Moreover, it must hold that
incy
 =
m_y
 if
incx
 =
m_x
 and that
incy
 = 1 if
incx
 = 1.
cs
,
sn
(global)
The parameters defining the properties of the planar rotation. It must hold that 0
≤
cs
,
sn
≤
 1 and that
sn
2
 +
cs
2
 = 1. The latter is hardly checked in finite precision arithmetics.
work
(local workspace) array of size
lwork
lwork
(local )
The length of the workspace array
work
.
If
incx
 = 1 and
incy
 = 1, then
lwork
 = 2*
m_x
If
lwork
 = -1, then a workspace query is assumed; the
function
only calculates the optimal size of the
work
 array, returns this value as the first entry of the IWORK array, and no error message related to LIWORK is issued by
pxerbla
.
OUTPUT Parameters
x
y
work
[0]
On exit, if
info
 = 0,
work
[0]
 returns the optimal
lwork
info
(global )
= 0: successful exit
< 0: if
info
 = -
i
, the
i
-th argument had an illegal value.
If the
i
-th argument is an array and the
j
-th entry
, indexed
j
-1,
 had an illegal value, then
info
 = -(
i
*100+
j
), if the
i
-th argument is a scalar and had an illegal value, then
info
 = -
i
.

Product and Performance Information

1

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