## Developer Reference

• 098
• 03/30/2020
• Public Content
Contents

# p?axpy

Computes a distributed vector-scalar product and adds the result to a distributed vector.

## Syntax

Include Files
• mkl_pblas.h
Description
The
p?axpy
routines perform the following operation with distributed vectors:
`sub(y) := sub(y) + a*sub(x)`
where:
a
is a scalar;
sub(
x
)
and
sub(
y
)
are
n
-element 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
n
(global)
INTEGER
.
The length of distributed vectors,
n
0.
a
(local)
REAL
for
psaxpy
DOUBLE PRECISION
for
pdaxpy
COMPLEX
for
pcaxpy
DOUBLE COMPLEX
for
pzaxpy
Specifies the scalar
a
.
x
(local)
REAL
for
psaxpy
DOUBLE PRECISION
for
pdaxpy
COMPLEX
for
pcaxpy
DOUBLE COMPLEX
for
pzaxpy
Array, size
(
jx
-1)*
m_x
+
ix
+(
n
-1)*abs(
incx
))
.
This array contains the entries of the distributed vector
sub(
x
)
.
ix
,
jx
(global)
INTEGER
.
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)
INTEGER
array of dimension 9. The array descriptor of the distributed matrix
X
.
incx
(global)
INTEGER
.
Specifies the increment for the elements of
sub(
x
)
. Only two values are supported, namely 1 and
m_x
.
incx
must not be zero.
y
(local)
REAL
for
psaxpy
DOUBLE PRECISION
for
pdaxpy
COMPLEX
for
pcaxpy
DOUBLE COMPLEX
for
pzaxpy
Array, size
(
jy
-1)*
m_y
+
iy
+(
n
-1)*abs(
incy
))
.
This array contains the entries of the distributed vector
sub(
y
)
.
iy
,
jy
(global)
INTEGER
.
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)
INTEGER
array of dimension 9. The array descriptor of the distributed matrix
Y
.
incy
(global)
INTEGER
.
Specifies the increment for the elements of
sub(
y
)
. Only two values are supported, namely 1 and
m_y
.
incy
<