MPI_Graph_create function

Makes a new communicator to which topology information has been attached.

Syntax

int MPIAPI MPI_Graph_create(
        MPI_Comm               comm_old,
        int                    nnodes,
        _In_count_(nnodes) int *index,
  _In_  int                    *edges,
        int                    reorder,
  _Out_ MPI_Comm               *comm_cart
);

Parameters

• comm_old
  Input communicator without topology.

• nnodes
  Number of nodes in graph.

• index
  Array of integers describing node degrees.

• edges [in]
  Array of integers describing graph edges.

• reorder
  Ranking may be reordered (true) or not (false).

• comm_cart [out]
  Communicator with graph topology added.

Return value

Returns MPI_SUCCESS on success. Otherwise, the return value is an error code.

In Fortran, the return value is stored in the IERROR parameter.

Fortran

    MPI_GRAPH_CREATE(COMM_OLD, NNODES, INDEX, EDGES, REORDER, COMM_GRAPH, IERROR)
        INTEGER COMM_OLD, NNODES, INDEX(*), EDGES(*), COMM_GRAPH, IERROR
        LOGICAL REORDER

Remarks

Each process must provide a description of the entire graph, not just the neigbors of the calling process.

MSMPI currently ignores the reorder info.

Requirements

See also

MPI Process Topology Functions