## Developer Reference

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

# mkl_sparse_?_qr

Calculates the solution of sparse systems of linear equations using QR decomposition.

## Syntax

Include Files
• mkl_sparse_qr.f90
Description
The
mkl_sparse_?_qr
routine calculates the solution of sparse systems of linear equations
A
*
x
=
b
using QR decomposition (
A
=
Q
*
R
).
Currently,
mkl_sparse_?_qr
supports only CSR format for the input matrix, non-transpose operation, and single right-hand side.
Input Parameters
operation
C_INT
Specifies the operation to perform.
Currently, the only suppored value is
SPARSE_OPERATION_NON_TRANSPOSE
(non-transpose case; that is,
A
*
x
=
b
is solved).
A
SPARSE_MATRIX_T
Handle containing a sparse matrix in an internal data structure.
descr
MATRIX_DESCR
Structure specifying sparse-matrix properties. Only the parameters listed here are currently supported.
type
Specifies the type of sparse matrix.
Currently, the only supported value is
SPARSE_MATRIX_TYPE_GENERAL
(the matrix is processed as-is).
layout
C_INT
Describes the storage scheme for the dense matrix:
 SPARSE_LAYOUT_COLUMN_MAJOR Storage of elements uses column-major layout. SPARSE_LAYOUT_ROW_MAJOR Storage of elements uses row-major layout.
x
C_FLOAT
for
mkl_sparse_s_qr
;
C_DOUBLE
for
mkl_sparse_d_qr
Array with a size of at least
rows
*
cols
:
 layout = SPARSE_LAYOUT_COLUMN_MAJOR layout = SPARSE_LAYOUT_ROW_MAJOR rows (number of rows in x ) ldx Number of columns in A cols (number of columns in x ) columns ldx
columns
C_INT
Number of columns in matrix
b
.
ldx
C_INT
Specifies the leading dimension of matrix
x
.
b
C_FLOAT
for
mkl_sparse_s_qr
;
C_DOUBLE
for
mkl_sparse_d_qr
Array with a size of at least
rows
*
cols
:
 layout = SPARSE_LAYOUT_COLUMN_MAJOR layout = SPARSE_LAYOUT_ROW_MAJOR rows (number of rows in b ) ldb Number of columns in A cols (number of columns in b ) columns ldb