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 indices and values are copied so the array space need not be provided with PetscMalloc().

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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