Once a graph topology is set up, it may be necessary to inquire about the topology. These functions are given below and are all local calls.

MPI_Graphdims_get(MPI_Comm comm, int *nnodes, int *nedges)

MPI_GRAPHDIMS_GET(COMM, NNODES, NEDGES, IERROR)INTEGER COMM, NNODES, NEDGES, IERROR

MPI_GRAPHDIMS_GET returns the number of nodes and the number of edges in the graph. The number of nodes is identical to the size of the group associated with comm. nnodes and nedges can be used to supply arrays of correct size for index and edges, respectively, in MPI_GRAPH_GET. MPI_GRAPHDIMS_GET would return nnodes = 4 and nedges = 6for Example .

MPI_Graph_get(MPI_Comm comm, int maxindex, int maxedges, int *index, int *edges)

MPI_GRAPH_GET(COMM, MAXINDEX, MAXEDGES, INDEX, EDGES, IERROR)INTEGER COMM, MAXINDEX, MAXEDGES, INDEX(*), EDGES(*), IERROR

MPI_GRAPH_GET returns index and edges as was supplied to MPI_GRAPH_CREATE. maxindex and maxedges are at least as big as nnodes and nedges, respectively, as returned by MPI_GRAPHDIMS_GET above. Using the comm created in Example would return the index and edges given in the example.

Fri Sep 1 06:16:55 EDT 1995