cluster_sparse_solver_get_csr

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 3/22/2024

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cluster_sparse_solver_get_csr_size

Computes the (local) number of rows and (local) number of nonzero entries for (distributed) CSR data corresponding to the provided name.

Syntax

void cluster_sparse_solver_get_csr_size (_MKL_DSS_HANDLE_t pt, _MKL_DSS_EXPORT_DATA name , MKL_INT *local_nrows, MKL_INT *local_nnz, const int*comm, MKL_INT *error);

Include Files

mkl_cluster_sparse_solver.h

Description

This routine uses the internal data created during the factorization phase of cluster_sparse_solver for matrix A. The routine then:

Computes the local number of rows and the local number of nonzeros for CSR data that correspond to the provided name
Returns the computed values in local_nrows and local_nnz

It is assumed that the CSR data defined by the name will be distributed in the same way as the matrix A (as defined by iparm[39]) used in cluster_sparse_solver.

The returned values can be used for allocating CSR arrays for factors L and U, and also for allocating arrays for permutations P and Q, or scaling matrix D which can then be used with cluster_sparse_solver_set_csr_ptrs or cluster_sparse_solver_set_ptr for exporting corresponding data via cluster_sparse_solver_export.

NOTE:

Only call this routine after the factorization phase (phase=22) of the cluster_sparse_solver has been called. Neither pt, nor iparm should be changed after the preceding call to cluster_sparse_solver.

Input Parameters

pt

Array with size of 64.

Handle to internal data structure used in the prior calls to cluster_sparse_solver.

CAUTION:

Do not modify pt after the calls to cluster_sparse_solver.

name

Specifies CSR data for which the output values are computed.

SPARSE_PTLUQT_L: Factor L from P*A*Q=L*U.
SPARSE_PTLUQT_U: Factor U from P*A*Q=L*U.
SPARSE_DPTLUQT_L: Factor L from P* (D^-1A)*Q=L*U.
SPARSE_DPTLUQT_U: Factor U from P* (D^-1A)*Q=L*U.

local_nrows

On entry, an array of size 1.

local_nnz

On entry, an array of size 1.

comm

MPI communicator. The solver uses the Fortran MPI communicator internally. Convert the MPI communicator to Fortran using the MPI_Comm_c2f() function. See the examples in the <install_dir>/examples directory.

Output Parameters

local_nrows

On output, the local number of rows for the CSR data which correspond to the name.

local_nnz

On output, the local number of nonzero entries for the CSR data which correspond to the name.

error

The error indicator:

error: Information
0: no error
-1: pt is a null pointer
-2: invalid pt
-3: invalid name
-4: unsupported name
-9: unsupported internal code path, consider switching off non-default iparm parameters for cluster_sparse_solver
-10: unsupported case when the matrix A is distributed among processes with overlap in the preceding calls to cluster_sparse_solver
-12: internal memory error

NOTE:

Refer to cl_solver_export_c.c for an example using this functionality.

Parent topic: Parallel Direct Sparse Solver for Clusters Interface

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