Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

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

p?gemv

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

Syntax

void psgemv
(
const char
*trans
,
const MKL_INT
*m
,
const MKL_INT
*n
,
const float
*alpha
,
const float
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
const float
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
,
const float
*beta
,
float
*y
,
const MKL_INT
*iy
,
const MKL_INT
*jy
,
const MKL_INT
*descy
,
const MKL_INT
*incy
);
void pdgemv
(
const char
*trans
,
const MKL_INT
*m
,
const MKL_INT
*n
,
const double
*alpha
,
const double
*a
,
const MKL_INT
*ia
,
const MKL_INT
*ja
,
const MKL_INT
*desca
,
const double
*x
,
const MKL_INT
*ix
,
const MKL_INT
*jx
,
const MKL_INT
*descx
,
const MKL_INT
*incx
,
const double
*beta
,
double
*y
,
const MKL_INT
*iy
,
const MKL_INT
*jy
,
const MKL_INT
*descy
,
const MKL_INT
*incy
);
void pcgemv
(
const char
*trans
,
const MKL_INT
*m
,
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 pzgemv
(
const char
*trans
,
const MKL_INT
*m
,
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?gemv
 routines perform a distributed matrix-vector operation defined as 
sub(y)  := alpha*sub(A)*sub(x) + beta*sub(y),
or 
sub(y)  := alpha*sub(A)'*sub(x) + beta*sub(y),
or 
sub(y)  := alpha*conjg(sub(A)')*sub(x) + beta*sub(y),
where
alpha
 and
beta
 are scalars,
sub(
A
) is a
m
-by-
n
 submatrix,
sub(
A
) =
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1)
,
sub(
x
)
 and
sub(
y
)
 are subvectors.
When
trans
 = '
N
'
 or
'
n
'
,
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
+
m
-1)
 if
incy
 =
m_y
, and
Y
(
iy
:
iy
+
m
-1,
jy
)
 if
incy
 = 1
.
When
trans
 = '
T
'
 or
'
t
'
, or
'
C
'
, or
'
c
'
,
sub(
x
)
 denotes
X
(
ix
,
jx
:
jx
+
m
-1)
 if
incx
 =
m_x
, and
X
(
ix
:
ix
+
m
-1,
jx
)
 if
incx
 = 1,
sub(
y
)
 denotes
Y
(
iy
,
jy
:
jy
+
n
-1)
 if
incy
 =
m_y
, and
Y
(
iy
:
iy
+
m
-1,
jy
)
 if
incy
 = 1
.
Input Parameters
trans
(global) Specifies the operation:
if
trans
= '
N
'
 or
'
n
'
, then
sub(
y
) :=
alpha
*sub(
A
)'*sub(
x
) +
beta
*sub(
y
)
;
if
trans
= '
T
'
 or
'
t
'
, then
sub(
y
) :=
alpha
*sub(
A
)'*sub(
x
) +
beta
*sub(
y
)
;
if
trans
= '
C
'
 or
'
c
'
, then
sub(
y
) :=
alpha
*conjg(sub
A
)')*sub(
x
) +
beta
*sub(
y
)
.
m
(global) Specifies the number of rows of the distributed matrix
sub(
A
)
,
m
≥
0.
n
(global) Specifies the number of columns of the distributed matrix
sub(
A
)
,
n
≥
0.
alpha
(global)
Specifies the scalar
alpha
.
a
(local)
Array, size
(
lld_a
, LOCq(
ja
+
n
-1))
. Before entry this array must contain the local pieces of the distributed matrix
sub(
A
)
.
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
(
jx
-1)*
m_x
 +
ix
+(
n
-1)*abs(
incx
))
 when
trans
 = '
N
'
 or
'n'
, and
(
jx
-1)*
m_x
 +
ix
+(
m
-1)*abs(
incx
))
 otherwise.
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
(
jy
-1)*
m_y
 +
iy
+(
m
-1)*abs(
incy
))
 when
trans
 = '
N
'
 or
'n'
, and
(
jy
-1)*
m_y
 +
iy
+(
n
-1)*abs(
incy
))
 otherwise.
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