Contents

# mkl_?skymv

Computes matrix - vector product for a sparse matrix in the skyline storage format with one-based indexing (deprecated).

## Syntax

Include Files
• mkl.h
Description
This routine is deprecated. Use mkl_sparse_?_mvfrom the
Intel® oneAPI Math Kernel Library
The
mkl_?skymv
routine performs a matrix-vector operation defined as
`y := alpha*A*x + beta*y`
or
`y := alpha*AT*x + beta*y,`
where:
alpha
and
beta
are scalars,
x
and
y
are vectors,
A
is an
m
-by-
k
sparse matrix stored using the skyline storage scheme,
A
T
is the transpose of
A
.
This routine supports only one-based indexing of the input arrays.
Input Parameters
transa
Specifies the operation.
If
transa
=
'N'
or
'n'
, then
y
:=
alpha
*
A
*
x
+
beta
*
y
If
transa
=
'T'
or
't'
or
'C'
or
'c'
, then
y
:=
alpha
*
A
T
*
x
+
beta
*
y
,
m
Number of rows of the matrix
A
.
k
Number of columns of the matrix
A
.
alpha
Specifies the scalar
alpha
.
matdescra
Array of six elements, specifies properties of the matrix used for operation. Only first four array elements are used, their possible values are given in
Table “Possible Values of the Parameter
matdescra
(
descra
)”
. Possible combinations of element values of this parameter are given in
Table “Possible Combinations of Element Values of the Parameter
matdescra
.
General matrices
(
matdescra

='G')
is not supported.
val
Array containing the set of elements of the matrix
A
in the skyline profile form.
If
matdescrsa

=
'L'
, then
val
contains elements from the low triangle of the matrix
A
.
If
matdescrsa

=
'U'
, then
val
contains elements from the upper triangle of the matrix
A
.
Refer to
values
array description in Skyline Storage Scheme for more details.
pntr
Array of length
(
m
+ 1)
for lower triangle, and
(
k
+ 1)
for upper triangle.
It contains the indices specifying in the
val
the positions of the first element in each row (column) of the matrix
A
. Refer to
pointers
array description in Skyline Storage Scheme for more details.
x
Array, size at least
k
if
transa
=
'N'
or
'n'
and at least
m
otherwise. On entry, the array
x
must contain the vector
x
.
beta
Specifies the scalar
beta
.
y
Array, size at least
m
if
transa
=
'N'
or
'n'
and at least
k
otherwise. On entry, the array
y
must contain the vector
y
.
Output Parameters
y
Overwritten by the updated vector
y
.

#### Product and Performance Information

1

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