Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

p?hemv

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

Syntax

call pchemv
(
uplo
,
n
,
alpha
,
a
,
ia
,
ja
,
desca
,
x
,
ix
,
jx
,
descx
,
incx
,
beta
,
y
,
iy
,
jy
,
descy
,
incy
)
call pzhemv
(
uplo
,
n
,
alpha
,
a
,
ia
,
ja
,
desca
,
x
,
ix
,
jx
,
descx
,
incx
,
beta
,
y
,
iy
,
jy
,
descy
,
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)
CHARACTER*1
.
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)
INTEGER
.
Specifies the order of the distributed matrix
sub(
A
)
,
n
0.
alpha
(global)
COMPLEX
for
pchemv
DOUBLE COMPLEX
for
pzhemv
Specifies the scalar
alpha
.
a
(local)
COMPLEX
for
pchemv
DOUBLE COMPLEX
for
pzhemv
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)
INTEGER
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