gmsh, parallel - reads #partitions an element is part of

Hi,

when reading files partitioned with gmsh via

  std::string l_loadOpts = "PARALLEL=BCAST_DELETE;";
              l_loadOpts += "PARTITION;";
              l_loadOpts += "PARALLEL_RESOLVE_SHARED_ENTS;";

  // load the mesh
  l_error = m_core.load_file( i_pathToMesh.c_str(), &m_mesh, l_loadOpts.c_str() );
  checkError( l_error );

moab reads the "third number" in

number-of-tags

    gives the number of integer tags that follow for the n-th element. By default, the first tag is the number of the physical entity to which the element belongs; the second is the number of the elementary geometrical entity to which the element belongs; the third is the number of mesh partitions to which the element belongs, followed by the partition ids (negative partition ids indicate ghost cells). A zero tag is equivalent to no tag. Gmsh and most codes using the MSH 2 format require at least the first two tags (physical and elementary tags).

http://gmsh.info/doc/texinfo/gmsh.html

This happens in line 294 of ReadGmsh.cpp:

    id_list.push_back(int_data[0]);
    part_set_list.push_back(tag_data.size() > 2 ? tag_data[2] : 0);
    geom_set_list.push_back(tag_data.size() > 1 ? tag_data[1] : 0);
     mat_set_list.push_back(tag_data.size() > 0 ? tag_data[0] : 0);

Can be fixed by reading 3 instead of 2 (not sure of side effects):

    part_set_list.push_back(tag_data.size() > 3 ? tag_data[3] : 0);
    geom_set_list.push_back(tag_data.size() > 1 ? tag_data[1] : 0);
     mat_set_list.push_back(tag_data.size() > 0 ? tag_data[0] : 0);

For the sake of completeness, here's the gmsh-geo ifle, attaching the mesh file:

// optimize mesh
Mesh.Lloyd=5;

// define mesh size
size = 9.424777960769379715387930149838508652591508198125317462924;

// define characteristic length
lc = 0.93;

//
// construct the square
//
Point(1) = { 0,    0,    0, lc };
Point(2) = { size, 0,    0, lc };
Point(3) = { size, size, 0, lc };
Point(4) = { 0,    size, 0, lc };

Line(1) = {1, 2};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 1};

Line Loop(101) = { 1, 2, 3, 4};
Plane Surface(201) = {101};

// define volume
Physical Surface("region_0") = {201};

mesh generated with

gmsh -2 mesh.geo -part 3

 gmsh --version
2.12.0

moab-version: 4.9.0

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