Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 0.9
  • 09/09/2020
  • Public Content
Contents

p?hemv

Computes a distributed matrix-vector product using a Hermitian matrix.

Syntax

void pchemv
(
const char
*uplo
,
const MKL_INT
*n
,
const MKL_Complex8
*alpha
,
const MKL_Complex8
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
const MKL_Complex8
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
,
const MKL_Complex8
*beta
,
MKL_Complex8
*y
,
const MKL_INT
*iy
,
const MKL_INT
*jy
,
const MKL_INT
*descy
,
const MKL_INT
*incy
);
void pzhemv
(
const char
*uplo
,
const MKL_INT
*n
,
const MKL_Complex16
*alpha
,
const MKL_Complex16
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
const MKL_Complex16
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
,
const MKL_Complex16
*beta
,
MKL_Complex16
*y
,
const MKL_INT
*iy
,
const MKL_INT
*jy
,
const MKL_INT
*descy
,
const MKL_INT
*incy
);
Include Files
  • mkl_pblas.h
Description
The
p?hemv
 routines perform a distributed matrix-vector operation defined as 
sub(y) := alpha*sub(A)*sub(x) + beta*sub(y),
where:
alpha
 and
beta
 are scalars,
sub(
A
)
 is a
n
-by-
n
 Hermitian distributed matrix,
sub(
A
)=
A
(
ia
:
ia
+
n
-1,
ja
:
ja
+
n
-1)
 ,
sub(
x
)
 and
sub(
y
)
 are distributed vectors.
sub(
x
)
 denotes
X
(
ix
,
jx
:
jx
+
n
-1)
 if
incx
 =
m_x
, and
X
(
ix
:
ix
+
n
-1,
jx
)
 if
incx
 = 1,
sub(
y
)
 denotes
Y
(
iy
,
jy
:
jy
+
n
-1)
 if
incy
 =
m_y
, and
Y
(
iy
:
iy
+
n
-1,
jy
)
 if
incy
 = 1
.
Input Parameters
uplo
(global) Specifies whether the upper or lower triangular part of the Hermitian distributed matrix
sub(
A
)
 is used:
If
uplo
 =
'U'
 or
'u'
, then the upper triangular part of the
sub(
A
)
 is used.
If
uplo
 =
'L'
 or
'l'
, then the low triangular part of the
sub(
A
)
 is used.
n
(global) Specifies the order of the distributed matrix
sub(
A
)
,
n
≥
 0.
alpha
(global)
Specifies the scalar
alpha
.
a
(local)
Array, size
(
lld_a
, LOCq(
ja
+
n
-1))
. This array contains the local pieces of the distributed matrix
sub(
A
)
.
Before entry when
uplo
 =
'U'
 or
'u'
, the
n
-by-
n
 upper triangular part of the distributed matrix
sub(
A
)
 must contain the upper triangular part of the Hermitian distributed matrix and the strictly lower triangular part of
sub(
A
)
 is not referenced, and when
uplo
 =
'L'
 or
'l'
, the
n
-by-
n
 lower triangular part of the distributed matrix
sub(
A
)
 must contain the lower triangular part of the Hermitian distributed matrix and the strictly upper triangular part of
sub(
A
)
 is not referenced.
ia
,
ja
(global) The row and column indices in the distributed matrix
A
 indicating the first row and the first column of the submatrix
sub(
A
)
, respectively.
desca
(global and local) array of dimension 9. The array descriptor of the distributed matrix
A
.
x
(local)
Array, size at least
(
jx
-1)*
m_x
 +
ix
+(
n
-1)*abs(
incx
))
.
This array contains the entries of the distributed vector
sub(
x
)
.
ix
,
jx
(global) The row and column indices in the distributed matrix
X
 indicating the first row and the first column of the submatrix
sub(
x
)
, respectively.
descx
(global and local) array of dimension 9. The array descriptor of the distributed matrix
X
.
incx
(global) Specifies the increment for the elements of
sub(
x
)
. Only two values are supported, namely 1 and
m_x
.
incx
 must not be zero.
beta
(global)
Specifies the scalar
beta
. When
beta
 is set to zero, then
sub(
y
)
 need not be set on input.
y
(local)
Array, size at least
(
jy
-1)*
m_y
 +
iy
+(
n
-1)*abs(
incy
))
.
This array contains the entries of the distributed vector
sub(
y
)
.
iy
,
jy
(global) The row and column indices in the distributed matrix
Y
 indicating the first row and the first column of the submatrix
sub(
y
)
, respectively.
descy
(global and local) array of dimension 9. The array descriptor of the distributed matrix
Y
.
incy
(global) Specifies the increment for the elements of
sub(
y
)
. Only two values are supported, namely 1 and
m_y
.
incy
 must not be zero.
Output Parameters
y
Overwritten by the updated distributed vector
sub(
y
)
.

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