Contents

# mkl_?csrsv

Solves a system of linear equations for a sparse matrix in the CSR format (deprecated).

## Syntax

Include Files
• mkl.h
Description
This routine is deprecated. Use mkl_sparse_?_trsvfrom the
Intel® oneAPI Math Kernel Library
Inspector-executor Sparse BLAS interface instead.
The
mkl_?csrsv
routine solves a system of linear equations with matrix-vector operations for a sparse matrix in the CSR format:
`y := alpha*inv(A)*x`
or
`y := alpha*inv(AT)*x,`
where:
alpha
is scalar,
x
and
y
are vectors,
A
is a sparse upper or lower triangular matrix with unit or non-unit main diagonal,
A
T
is the transpose of
A
.
This routine supports a CSR format both with one-based indexing and zero-based indexing.
Input Parameters
transa
Specifies the system of linear equations.
If
transa
=
'N'
or
'n'
, then
y
:=
alpha
*inv(
A
)*
x
If
transa
=
'T'
or
't'
or
'C'
or
'c'
, then
y
:=
alpha
*inv(
A
T
)*
x
,
m
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
.
val
Array containing non-zero elements of the matrix
A
.
Its length is
pntre
[
m
- 1] -
pntrb
[0]
.
Refer to
values
array description in CSR Format for more details.
The non-zero elements of the given row of the matrix must be stored in the same order as they appear in the row (from left to right).
No diagonal element can be omitted from a sparse storage if the solver is called with the non-unit indicator.
indx
For one-based indexing, array containing the column indices plus one for each non-zero element of the matrix
A
. For zero-based indexing, array containing the column indices for each non-zero element of the matrix
A
.
Its length is equal to length of the
val
array.
Refer to
columns
array description in CSR Format for more details.
Column indices must be sorted in increasing order for each row.
pntrb
Array of length
m
.
This array contains row indices, such that
pntrb
[
i
] -
pntrb
[0]
is the first index of row
i
in the arrays
val
and
indx
.
Refer to
pointerb
array description in CSR Format for more details.
pntre
Array of length
m
.
This array contains row indices, such that
pntre
[
i
] -
pntrb
[0] - 1
is the last index of row
i
in the arrays
val
and
indx
.
Refer to
pointerE
array description in CSR Format for more details.
x
Array, size at least
m
.
On entry, the array
x
must contain the vector
x
. The elements are accessed with unit increment.
y
Array, size at least
m
.
On entry, the array
y
must contain the vector
y
. The elements are accessed with unit increment.
Output Parameters
y
Contains solution vector
x
.

#### Product and Performance Information

1

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