neighbors_to_metis_graph


neighbors_to_metis_graph, a MATLAB code which reads a file describing the graph-theoretic adjacency structure of the elements in a mesh of triangles or tetrahedrons and writes out a similar file that is suitable for input to the mesh partitioning program metis.

Since we know we are dealing with a triangle or tet mesh, each "node" of the adjacency graph has 3 or 4 potential edges. If a potential edge is not used (in other words, if a face is a boundary face), then by convention we write out a "-1" for the neighbor value. Otherwise, the adjacency information lists the index of the element that is a neighbor on that face of the element

Converting to a METIS GRAPH format is trivial. We include an initial line that lists the number of "nodes" (elements) and "edges" (interfaces between pairs of elements), followed by, for each node (element), a list of the adjacent nodes (a list of the adjacent elements, omitting the "-1" values). A cross-eyed schoolboy sitting on a tack would be able to carry out this task!

Usage:

neighbors_to_metis_graph ( 'neighbor_file' )
where reads the data in 'neighbor_file', rearranges it to suit metis(), and writes out the modified data to 'metis_graph_file'.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

neighbors_to_metis_graph is available in a C++ version and a FORTRAN90 version and a MATLAB version.

Related Programs:

metis_test, a C code which calls metis(), which partitions the nodes of a graph or the elements of a mesh, for division among a number of parallel processes, or to reorder the variables in a sparse matrix to minimize fillin;

metis_graph, a data directory which contains examples of METIS GRAPH files, the format for graphs to be read by METIS, which can partition a graph;

neighbors_to_metis_graph_test

tet_mesh_tet_neighbors, a MATLAB code which reads information about a tet mesh and writes out a list of the tetrahedrons that are adjacent to a given tetrahedron;

triangulation_triangle_neighbors, a MATLAB code which reads data defining a triangulation, determines the neighboring triangles of each triangle, and writes that information to a file.

Reference:

  1. George Karypis, Vipin Kumar,
    METIS, a Software Package for Partitioning Unstructured Graphs and Computing Fill-Reduced Orderings of Sparse Matrices;

Source Code:

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Last revised on 21 February 2019.