Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 6/24/2024
Public

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mkl_sparse_?_sorv

Computes forward, backward sweeps or a symmetric successive over-relaxation preconditioner operation.

Syntax

stat = sparse_status_t mkl_sparse_s_sorv(type, descrA, A, omega, alpha, x, b)
      
stat = sparse_status_t mkl_sparse_d_sorv(type, descrA, A, omega, alpha, x, b)
      

Include Files

  • mkl_spblas.f90

Description

The mkl_sparse_?_sorv routine performs one of the following operations:

SPARSE_SOR_FORWARD:


SPARSE_SOR_BACKWARD:


SPARSE_SOR_SYMMETRIC: Performs application of a


preconditioner.

where A = L + D + U and x^0 is an input vector x scaled by input parameter alpha vector and x^1 is an output stored in vector x.

NOTE:

Currently this routine only supports the following configuration:

  • CSR format of the input matrix
  • SPARSE_SOR_FORWARD operation
  • General matrix (descr.type is SPARSE_MATRIX_TYPE_GENERAL) or symmetric matrix with full portrait and unit diagonal (descr.type is SPARSE_MATRIX_TYPE_SYMMETRIC, descr.mode is SPARSE_FILL_MODE_FULL, and descr.diag is SPARSE_DIAG_UNIT)
NOTE:

Currently, this routine is optimized only for sequential threading execution mode.

WARNING:
It is currently not allowed to place a sorv call in a parallel section (e.g., under #pragma omp parallel), because it is not thread-safe in this scenario. This limitation will be addressed in one of the upcoming releases.

Product and Performance Information

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

Notice revision #20201201

Input Parameters

type

SPARSE_MATRIX_T.

Specifies the operation performed by the SORV preconditioner.

SPARSE_SOR_FORWARD

Performs forward sweep as defined by:


SPARSE_SOR_BACKWARD

Performs backward sweep as defined by:


SPARSE_SOR_SYMMETRIC

Preconditioner matrix could be expressed as:


descr

MATRIX_DESCR.

Structure specifying sparse matrix properties.

SPARSE_MATRIX_T type

Specifies the type of a sparse matrix:

  • SPARSE_MATRIX_TYPE_GENERAL

    The matrix is processed as-is.

  • SPARSE_MATRIX_TYPE_SYMMETRIC

    The matrix is symmetric (only the requested triangle is processed).

  • SPARSE_MATRIX_TYPE_HERMITIAN

    The matrix is Hermitian (only the requested triangle is processed).

  • SPARSE_MATRIX_TYPE_TRIANGULAR

    The matrix is triangular (only the requested triangle is processed).

  • SPARSE_MATRIX_TYPE_DIAGONAL

    The matrix is diagonal (only diagonal elements are processed).

  • SPARSE_MATRIX_TYPE_BLOCK_TRIANGULAR

    The matrix is block-triangular (only requested triangle is processed). Applies to BSR format only.

  • SPARSE_MATRIX_TYPE_BLOCK_DIAGONAL

    The matrix is block-diagonal (only diagonal blocks are processed). Applies to BSR format only.

C_INT mode

Specifies the triangular matrix part for symmetric, Hermitian, triangular, and block-triangular matrices:

  • SPARSE_FILL_MODE_LOWER

    The lower triangular matrix part is processed.

  • SPARSE_FILL_MODE_UPPER

    The upper triangular matrix part is processed.

SPARSE_MATRIX_TYPE_DIAGONAL diag

Specifies diagonal type for non-general matrices:

  • SPARSE_DIAG_NON_UNIT

    Diagonal elements might not be equal to one.

  • SPARSE_DIAG_UNIT

    Diagonal elements are equal to one.

A

SPARSE_MATRIX_T.

Handle containing internal data.

omega

C_FLOAT.

Relaxation factor.

alpha

C_FLOAT.

Parameter that could be used to normalize or set to zero the vector x that holds the initial guess.

x

C_FLOAT.

Initial guess on input.

b

C_FLOAT.

Right-hand side.

Output Parameters

x

C_FLOAT.

Solution vector on output.

stat

INTEGER

Value indicating whether the operation was successful or not, and 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.