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build_subdomain_map() grouped elements by subdomain id alone, so a
subdomain containing more than one element type (e.g. a mix of
C0POLYHEDRON and HEX8 cells) became a single Exodus block whose type was
taken from its first element. That either errored ("all elements with a
given subdomain ID [must] be the same type") or, when the first element
was a standard type, crashed in ex_put_concat_all_blocks while writing
the polyhedra as that type.
Group elements by (subdomain, element type): single-type subdomains keep
their previous block id and behavior, while additional element types in a
subdomain get synthesized block ids. Exodus requires a single element
type per block, so this is what lets a mixed polyhedron/hex mesh be
written and read back.
Adds test_write_and_read_mixed_poly_hex, which round-trips a mesh with a
C0POLYHEDRON and a HEX8 in the same subdomain.
Co-Authored-By: Claude <noreply@anthropic.com>
GiudGiud
marked this pull request as ready for review
September 17, 2026 13:33
GiudGiud
commented
Sep 17, 2026
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| const subdomain_id_type block_id = | ||
| first_type ? sbd_id : next_synth_block_id++; |
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do we want a warning here? or just an info message
I m leaning info message, and adding the new entry into a subdomain name map
GiudGiud
commented
Sep 17, 2026
Comment on lines
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| // subdomain id. This block becomes its own subdomain when | ||
| // the file is read back in. |
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that might be undesirable but also merging someone's random mesh same-name blocks (to try to recover the original subdomain assignments from subdomains names being the same and IDs being different) might also not work well
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moose failures expected, patch here: |
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refs #4019
I need this because when reading from VTK and outputting to exodus straight away (to keep my pipeline with exodus in MOOSE, maybe I don't need to though), I dont have a step in libmesh to fix the element block assignments. I only have that in moose
build_subdomain_map() grouped elements by subdomain id alone, so a subdomain containing more than one element type (e.g. a mix of C0POLYHEDRON and HEX8 cells) became a single Exodus block whose type was taken from its first element. That either errored ("all elements with a given subdomain ID [must] be the same type") or, when the first element was a standard type, crashed in ex_put_concat_all_blocks while writing the polyhedra as that type.
Group elements by (subdomain, element type): single-type subdomains keep their previous block id and behavior, while additional element types in a subdomain get synthesized block ids. Exodus requires a single element type per block, so this is what lets a mixed polyhedron/hex mesh be written and read back.
Adds test_write_and_read_mixed_poly_hex, which round-trips a mesh with a C0POLYHEDRON and a HEX8 in the same subdomain.