cluster_sparse_solver_get_csr

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 10/15/2026

Version

Public

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 .

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 .

name

Specifies CSR data for which the output values are computed.

`SPARSE_PTLUQT_L`	Factor L from `\(P\cdot A \cdot Q = L \cdot U\)`.
`SPARSE_PTLUQT_U`	Factor U from `\(P\cdot A \cdot Q = L \cdot U\)`.
`SPARSE_DPTLUQT_L`	Factor L from `\(P \cdot (D^{-1}A) \cdot Q = L \cdot U\)`.
`SPARSE_DPTLUQT_U`	Factor U from `\(P \cdot (D^{-1}A) \cdot Q = L \cdot U\)`.

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.

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