MatCreateMPIAdj

Creates a sparse matrix representing an adjacency list. The matrix need not have numerical values associated with it, it is intended for ordering (to reduce bandwidth etc) and partitioning.

Synopsis

#include "petscmat.h" 
PetscErrorCode MatCreateMPIAdj(MPI_Comm comm, PetscInt m, PetscInt N, PetscInt *i, PetscInt *j, PetscInt *values, Mat *A)

Collective

Input Parameters

• comm - MPI communicator

• m - number of local rows

• N - number of global columns

• i - the indices into j for the start of each row

• j - the column indices for each row (sorted for each row).

• values - the values, optional, use NULL if not provided

Output Parameter

• A - the matrix

Notes

The indices in i and j start with zero (NOT with one).

You must NOT free the i, values and j arrays yourself. PETSc will free them when the matrix is destroyed; you must allocate them with PetscMalloc().

You should not include the matrix diagonals.

If you already have a matrix, you can create its adjacency matrix by a call to MatConvert(), specifying a type of MATMPIADJ.

Possible values for MatSetOption() - MAT_STRUCTURALLY_SYMMETRIC

Fortran Note

From Fortran the arrays indices and values must be retained by the user until A is destroyed

See Also

Matrices, Mat, MatCreate(), MatConvert(), MatGetOrdering(), MATMPIADJ, MatMPIAdjSetPreallocation()

Level

intermediate

Location

src/mat/impls/adj/mpi/mpiadj.c

Examples

src/mat/tutorials/ex11.c

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