mkl_sparse_?_qr

First stage of the solving step of the SPARSE QR solver.

Syntax

stat = mkl_sparse_d_qr_qmult (operation, A, layout, x, columns, ldx, b, ldb)

stat = mkl_sparse_s_qr_qmult (operation, A, layout, x, columns, ldx, b, ldb)

Include Files

mkl_sparse_qr.f90

Description

The mkl_sparse_?_qr_qmult routine computes multiplication of inversed matrix Q and right-hand side matrix b. This routine can be used to perform the solving step in two separate calls as an alternative to a single call of mkl_sparse_?_qr_solve.

Note

Currently, mkl_sparse_?_qr_qmult 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.

Note

Currently, the only supported 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.

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

ldb

C_INT

Specifies the leading dimension of matrix b.

Output Parameters

x

C_FLOAT for mkl_sparse_s_qr; C_DOUBLE for mkl_sparse_d_qr

Overwritten by the updated matrix x = Q^-1*b.

stat

INTEGER

Value indicating whether the operation was successful, and if not, why:

`SPARSE_STATUS_SUCCESS`	The operation was successful.
`SPARSE_STATUS_NOT_INITIALIZED`	The routine encountered an empty handle or matrix array.
`SPARSE_STATUS_ALLOC_FAILED`	Internal memory allocation failed.
`SPARSE_STATUS_INVALID_VALUE`	The input parameters contain an invalid value.
`SPARSE_STATUS_EXECUTION_FAILED`	Execution failed.
`SPARSE_STATUS_INTERNAL_ERROR`	An error in algorithm implementation occurred.
`SPARSE_STATUS_NOT_SUPPORTED`	The requested operation is not supported.