Contents

# mkl_?csrtrsv

Triangular solvers with simplified interface for a sparse matrix in the CSR format (3-array variation) with one-based indexing (deprecated).

## Syntax

Include Files
• mkl.h
Description
This routine is deprecated. Use mkl_sparse_?_trsvfrom the
Intel® oneAPI Math Kernel Library
The
mkl_?csrtrsv
routine solves a system of linear equations with matrix-vector operations for a sparse matrix stored in the CSR format (3 array variation):
`A*y = x`
or
`AT*y = x,`
where:
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 only one-based indexing of the input arrays.
Input Parameters
uplo
Specifies whether the upper or low triangle of the matrix
A
is used.
If
uplo
=
'U'
or
'u'
, then the upper triangle of the matrix
A
is used.
If
uplo
=
'L'
or
'l'
, then the low triangle of the matrix
A
is used.
transa
Specifies the system of linear equations.
If
transa
=
'N'
or
'n'
, then
A
*
y
=
x
If
transa
=
'T'
or
't'
or
'C'
or
'c'
, then
A
T
*
y
=
x
,
diag
Specifies whether
A
is unit triangular.
If
diag
=
'U'
or
'u'
, then
A
is a unit triangular.
If
diag
=
'N'
or
'n'
, then
A
is not unit triangular.
m
Number of rows of the matrix
A
.
a
Array containing non-zero elements of the matrix
A
. Its length is equal to the number of non-zero elements in the matrix
A
. Refer to
values
array description in Sparse Matrix Storage Formats 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.
ia
Array of length
m
+ 1
, containing indices of elements in the array
a
, such that
ia
[
i
] -
ia
[0]
is the index in the array
a
of the first non-zero element from the row
i
. The value of the last element
ia
[
m
] -
ia
[0]
is equal to the number of non-zeros. Refer to
rowIndex
array description in Sparse Matrix Storage Formats for more details.
ja
Array containing the column indices
plus one
for each non-zero element of the matrix
A
.
Its length is equal to the length of the array
a
. Refer to
columns
array description in Sparse Matrix Storage Formats for more details.
Column indices must be sorted in increasing order for each row.
x
Array, size is
m
.
On entry, the array
x
must contain the vector
x
.
Output Parameters
y
Array, size at least
m
.
Contains the vector
y
.

#### Product and Performance Information

1

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