Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
mkl_sparse_?_symgs
Computes a single step of the symmetric Gauss-Seidel preconditioner.
Syntax
stat = mkl_sparse_s_symgs ( op, A, descr, alpha, b, x )
stat = mkl_sparse_d_symgs ( op, A, descr, alpha, b, x )
stat = mkl_sparse_c_symgs ( op, A, descr, alpha, b, x )
stat = mkl_sparse_z_symgs ( op, A, descr, alpha, b, x )Include Files
mkl_spblas.f90
Description
The mkl_sparse_?_symgs routine performs this series of triangular solve and matrix-vector multiplication operations:
\[x^{0} &\leftarrow \alpha\cdot x \\ (L + D)\cdot x^{1} &= b - U\cdot x^{0} \\ (U + D)\cdot x &= b - L\cdot x^{1}\]
where \(A = L + D + U\) is a decomposition of \(A\) into strictly lower, diagonal and upper triangular parts.
Input Parameters
op
C_INT.
Specifies operation on input matrix \(A\).
operation |
Description |
|---|---|
SPARSE_OPERATION_NON_TRANSPOSE |
\(op(A) = A\) |
operation |
Description |
|---|---|
SPARSE_OPERATION_TRANSPOSE |
\(op(A) = A^{T}\) |
SPARSE_OPERATION_CONJUGATE_TRANSPOSE |
\(op(A) = A^{H}\) |
A
SPARSE_MATRIX_T.
Handle which contains the sparse matrix \(A\) .
alpha
C_FLOAT |
for mkl_sparse_s_symgs |
C_DOUBLE |
for mkl_sparse_d_symgs |
C_FLOAT_COMPLEX |
for mkl_sparse_c_symgs |
C_DOUBLE_COMPLEX |
for mkl_sparse_z_symgs |
Specifies the scalar, \(\alpha\) .
descr
MATRIX_DESCR .
Descriptor specifying sparse matrix properties.
sparse_matrix_type_t type |
Specifies the type of a sparse matrix:
|
sparse_fill_mode_t mode |
Specifies the triangular matrix part for symmetric, Hermitian, triangular, and block-triangular matrices:
|
sparse_diag_type_t diag |
Specifies diagonal type for non-general matrices:
|
x
C_FLOAT |
for mkl_sparse_s_symgs |
C_DOUBLE |
for mkl_sparse_d_symgs |
C_FLOAT_COMPLEX |
for mkl_sparse_c_symgs |
C_DOUBLE_COMPLEX |
for mkl_sparse_z_symgs |
Array of size at least \(m\) , where \(m\) is the number of rows of matrix \(A\) . On entry, the array x must contain the vector x .
b
C_FLOAT |
for mkl_sparse_s_symgs |
C_DOUBLE |
for mkl_sparse_d_symgs |
C_FLOAT_COMPLEX |
for mkl_sparse_c_symgs |
C_DOUBLE_COMPLEX |
for mkl_sparse_z_symgs |
Array of size at least \(m\) , where \(m\) is the number of rows of matrix \(A\) . On entry, the array b must contain the vector b .
Output Parameters
- x
-
Overwritten by the computed vector, \(x\) .
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. |
Return Values
See Output Parameter stat.