Hello,Just finished upgrading to the 1.5.0 release. Very excited about dg parallel so thank you for all the hard work.
I noticed in some of my test cases that use meshes converted from gmsh using dolfin-convert now fail when assembling facet wise in SystemAssembler. This appears to be caused by a new assumption, that any facet will only have one neighboring cell for which that facet is local facet 0. This assumption appears to be true for internally generated meshes but not for gmsh meshes converted using dolfin-convert.
I'm attaching a unit test that demonstrates the problem using dolfin-1.5.0 (though there are no changes to meshconvert.py or SystemAssembler.cpp between dolfin-1.5.0 and master that would fix this). This is based on test_system_assembler.py and runs test_facet_assembly_cellwise_insertion twice, once with an internal UnitInterval mesh and once with a gmsh unit interval mesh converted using dolfin-convert. The first run passes but the second fails because cell_index gets set to a single value for both neighboring cells at SystemAssembler.cpp:714 and then used to access the cell_dofs for both cells at SystemAssembler.cpp:747. This is fine if only one of the neighboring cells has the facet as local facet 0 but causes the matrix (in this case a simple P0 mass matrix) to have double values inserted for some cells and nothing inserted on the diagonal elsewhere. More generally this assumption crops up in other places that don't affect this test case. For example, cell_integrals and tensor_required_cell make the same assumption.
I've hacked around and removed the assumptions in a branch (https://bitbucket.org/tferma/dolfin/branch/systemassemblertensorrequiredfix) to confirm that it fixes my test cases (which it does) but I wanted to check whether this was intentional or not. Is it now a required that every facet only has a single neighboring cell for which that facet is local facet 0? If so I guess gmsh conversion in mshconvert.py needs fixing instead and I'd appreciate any tips on ensuring this.
Any advice much appreciated. Many thanks, Cian
facetwise_failure.tar.gz
Description: application/gzip
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