Enable MultiApp transfers between MFEM and libMesh problems on CPU by alexanderianblair · Pull Request #32315 · idaholab/moose

alexanderianblair · 2026-02-06T12:51:53Z

PR to enable transfers between transfers between MFEM GridFunctions and libMesh solutions on CPU, leveraging newly added GSLib interpolators for interpolation of MFEM GridFunctions at arbitrary sets of points.

Adds three new transfer classes, for transfers between arbitrary meshes in 2D and 3D using shape function evaluations for:

transfers from libMesh to MFEM, for first and second order LAGRANGE variables and constant MONOMIALs
transfers from MFEM to libMesh, for first and second order scalar H1 conforming variables and constant L2 vars,
transfers from MFEM to MFEM, for both scalar and vector FE types defined on H1, ND, RT, and L2 conforming FE spaces.

The newly added MFEM to MFEM transfer class is based off the MFEM gslib/field-interp miniapp. Interpolation and projection of libMesh variables in libMesh to MFEM and MFEM to libMesh transfers respectively is based off of existing implementations in MultiAppGeneralFieldTransfer and MultiAppShapeEvaluationTransfer.

Closes #31982

moosebuild · 2026-02-25T18:41:19Z

Job Documentation, step Docs: sync website on 58a80e6 wanted to post the following:

View the site here

This comment will be updated on new commits.

moosebuild · 2026-02-26T19:52:55Z

Job Coverage, step Generate coverage on 58a80e6 wanted to post the following:

Framework coverage

	953c57	#32315 58a80e
	Total	Total	+/-	New
Rate	85.87%	85.89%	+0.02%	100.00%
Hits	132288	132622	+334	429
Misses	21776	21791	+15	0

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Coverage did not change

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This comment will be updated on new commits.

moosebuild · 2026-03-04T10:54:13Z

Job Coverage, step Verify coverage on 3057f8e wanted to post the following:

The following coverage requirement(s) failed:

Failed to generate richards coverage rate (required: 93.0%)

moosebuild · 2026-03-04T11:17:21Z

Job Coverage, step Verify coverage on 3057f8e wanted to post the following:

The following coverage requirement(s) failed:

Failed to generate richards coverage rate (required: 93.0%)

moosebuild · 2026-03-09T14:35:29Z

Job Disable HDF5 on 1dbcc43 : invalidated by @loganharbour

moosebuild · 2026-04-23T20:35:26Z

Job Precheck, step Clang format on c1f2cf7 wanted to post the following:

Your code requires style changes.

A patch was auto generated and copied here
You can directly apply the patch by running, in the top level of your repository:

curl -s https://mooseframework.inl.gov/docs/PRs/32315/clang_format/style.patch | git apply -v

Alternatively, with your repository up to date and in the top level of your repository:

git clang-format 93d5d4fe012870b41ba034e856781d1e421f0bf9

…nsfer loops, and fix docstrings

lindsayad

I'm giving my approval contingent on my one remaining conversation being resolved, tests passing, and Nuno's review being met 😄

…tory

…uationTransfer and add 1-to-N test

nmnobre

One question:

What's the reason for using a different idiom to get libMesh's system in the libMesh->MFEM vs MFEM->libMesh transfer implementations?

One commit: nmnobre@5c259a0

Fixes a time section's (now) outdated description and a few of comments
Swaps the switch stmts with loops (sorry I didn't suggest this last time)
Reorders/simplifies some loop/if statements to reuse work or for early exit
Replaces getProblemData().cmplx_gridfunctions.Get() idioms with getComplexGridFunction()
Replaces dynamic_cast<MFEMProblem *>() with static_cast<MFEMProblem &>() where we already know it's safe to do so
Removes trailing whitespace in the tests file

nmnobre

Though noting I'd like an answer above for completeness, I'm happy with this now.
Thanks for this Alex, very nice work.

In the future, besides the many-to-many transfers, it'd be cool if we could hide the type of transfer from the user, e.g. if the user wants a shape evaluation transfer, perhaps we could determine programatically if it needs to be libMesh->MFEM or MFEM->libMesh or MFEM->MFEM or libMesh->libMesh? Just a thought.

nmnobre

Arrrgh... This (inadvertently I'm sure) reverts the change that @k-collie did to square.e in #32494, so we need to put that back (and perhaps rename square_quad.e as square_quad9.e?

alexanderianblair · 2026-04-29T00:51:35Z

One question:

* What's the reason for using a different idiom to get libMesh's system in the libMesh->MFEM vs MFEM->libMesh transfer implementations?

This could be changed - the reasons are historic. The

System * to_sys = find_sys(es, var_name); approach is based off of the similar usage in MultiAppGeneralFieldTransfer, and
System & from_sys = from_var.sys().system(); usage is based off of MultiAppGeneralFieldShapeEvaluationTransfer.

Since to_var is a const reference, using the second approach to determine to_sys in the MFEM->libMesh route would return a const reference to the system, which is not what we want here, as we need to set the DoFs on the new system. I generally think the latter is more expressive/readable though.

Co-authored-by: Nuno Nobre <nuno.nobre@stfc.ac.uk>

…re_quad9.e

alexanderianblair · 2026-04-29T01:22:11Z

Arrrgh... This (inadvertently I'm sure) reverts the change that @k-collie did to square.e in #32494, so we need to put that back (and perhaps rename square_quad.e as square_quad9.e?

This was indeed a mistake - I've fixed this and renamed square_quad.e to square_quad9.e as suggested.

moosebuild · 2026-04-29T02:22:54Z

Job Test, step Results summary on 58a80e6 wanted to post the following:

Framework test summary

Compared against 953c577 in job civet.inl.gov/job/3779372.

Removed tests

Test	Time (s)	Memory (MB)
`mfem/transfers/h1_mfem_parent_mfem_sub.ComplexToSubFromParent/run`	0.65	133.52
`mfem/transfers/h1_mfem_parent_mfem_sub.FromSubToParent/run`	0.64	130.62
`mfem/transfers/h1_mfem_parent_mfem_sub.ComplexFromSubToParent/run`	0.64	61.83
`mfem/transfers/h1_mfem_parent_mfem_sub.ToSubFromParent/run`	0.63	55.79
`mfem/transfers/h1_mfem_sub_mfem_sub.test/run`	0.61	131.52
`mfem/transfers/h1_mfem_parent_mfem_sub.ComplexToSubFromParent/verify`	0.06	0.00
`mfem/transfers/h1_mfem_sub_mfem_sub.test/verify`	0.04	0.00
`mfem/transfers/h1_mfem_parent_mfem_sub.ToSubFromParent/verify`	0.04	0.00
`mfem/transfers/h1_mfem_parent_mfem_sub.ComplexFromSubToParent/verify`	0.01	0.00
`mfem/transfers/h1_mfem_parent_mfem_sub.FromSubToParent/verify`	0.00	0.00
`mfem/transfers/h1_mfem_sub_mfem_sub.error`	SKIP	0.00

Added tests

Test	Time (s)	Memory (MB)
`mfem/transfers/sibling_transfers.MFEM_to_MFEM_sibling_transfers/1_to_N_nodal`	0.89	126.83
`mfem/transfers/sibling_transfers.libMesh_to_MFEM_sibling_transfers/1_to_N_nodal_parallel`	0.86	166.94
`mfem/transfers/sibling_transfers.MFEM_to_libMesh_sibling_transfers/1_to_N_nodal`	0.86	153.38
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1TetToHexSecondOrder`	0.86	124.85
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/VectorTransfer/Tetra`	0.85	103.49
`mfem/transfers/sibling_transfers.MFEM_to_MFEM_sibling_transfers/1_to_N_nodal_parallel`	0.84	152.45
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/VectorTransfer/TetToHex`	0.83	124.24
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1HexSecondOrder`	0.81	140.64
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1TetSecondOrder`	0.80	147.63
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1TriSecondOrder`	0.80	154.48
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1TetToHexSecondOrder`	0.79	117.28
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1HexSecondOrder`	0.78	132.24
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1QuadSecondOrder`	0.77	126.23
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1Tet`	0.75	136.88
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1TriToQuadSecondOrder`	0.75	136.60
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1TetSecondOrder`	0.75	138.14
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1QuadSecondOrder`	0.75	141.12
`mfem/transfers/sibling_transfers.MFEM_to_MFEM_sibling_transfers/nodal_mixed_mesh`	0.74	113.59
`mfem/transfers/sibling_transfers.libMesh_to_MFEM_sibling_transfers/nodal_elem`	0.73	102.99
`mfem/transfers/sibling_transfers.MFEM_to_libMesh_sibling_transfers/nodal_elem`	0.72	90.49
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1TriSecondOrder`	0.72	127.48
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1TetToHex`	0.72	147.67
`mfem/transfers/sibling_transfers.libMesh_to_MFEM_sibling_transfers/nodal_mixed_mesh`	0.71	127.25
`mfem/transfers/sibling_transfers.libMesh_to_MFEM_sibling_transfers/elem_elem`	0.71	85.95
`mfem/transfers/sibling_transfers.MFEM_to_MFEM_sibling_transfers/nodal_nodal`	0.71	104.27
`mfem/transfers/displaced.MFEMTransferFromlibMeshDisplaced`	0.71	155.45
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1TetToHex`	0.71	81.80
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/VectorTransfer/Hex`	0.71	96.87
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1Tri`	0.71	130.47
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1Hex`	0.70	95.41
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1TriToQuad`	0.70	79.55
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1Tet`	0.70	119.90
`mfem/transfers/l2_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/L2Tet`	0.70	164.43
`mfem/transfers/sibling_transfers.MFEM_to_libMesh_sibling_transfers/nodal_nodal`	0.69	97.99
`mfem/transfers/sibling_transfers.libMesh_to_MFEM_sibling_transfers/nodal_nodal`	0.69	109.63
`mfem/transfers/sibling_transfers.MFEM_to_libMesh_sibling_transfers/elem_elem`	0.69	107.32
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1Quad`	0.68	130.23
`mfem/transfers/displaced.MFEMTransferTolibMeshDisplaced`	0.68	92.60
`mfem/transfers/h1_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/H1Hex`	0.67	105.25
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/OutOfMesh/Hex`	0.67	102.86
`mfem/transfers/l2_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/L2TetToHex`	0.67	60.77
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1TriToQuad`	0.67	108.27
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1Tri`	0.66	64.82
`mfem/transfers/l2_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/L2Hex`	0.66	130.52
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1Quad`	0.65	124.74
`mfem/transfers/l2_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/L2Tet`	0.65	130.06
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/ComplexFromSubToParent/run`	0.64	103.33
`mfem/transfers/l2_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/L2TetToHex`	0.64	98.66
`mfem/transfers/l2_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/L2Tri`	0.63	70.17
`mfem/transfers/l2_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/L2TriToQuad`	0.63	131.39
`mfem/transfers/mfem_sub_mfem_sub.MFEMCopyTransfer/test/run`	0.63	125.47
`mfem/transfers/l2_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/L2TriToQuad`	0.63	52.93
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/ToSubFromParent/run`	0.63	67.40
`mfem/transfers/l2_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/L2Quad`	0.63	81.74
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/FromSubToParent/run`	0.63	87.02
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/ComplexToSubFromParent/run`	0.62	88.59
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/FromSubToParent/run`	0.62	139.48
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/ComplexFromSubToParent/run`	0.62	144.93
`mfem/transfers/l2_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/L2Quad`	0.62	97.14
`mfem/transfers/l2_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/L2Tri`	0.62	65.43
`mfem/transfers/h1_mfem_parent_libmesh_sub.MFEMTransferFromlibMesh/H1TriToQuadSecondOrder`	0.61	101.19
`mfem/transfers/l2_libmesh_parent_mfem_sub.MFEMTransferTolibMesh/L2Hex`	0.61	80.02
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/ComplexFromSubToParent/verify`	0.13	0.00
`mfem/transfers/mfem_sub_mfem_sub.MFEMCopyTransfer/test/verify`	0.04	0.00
`mfem/transfers/mfem_parent_mfem_sub.MFEMShapeEvaluationTransfer/FromSubToParent/verify`	0.03	0.00
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/ComplexToSubFromParent/verify`	0.02	0.00
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/ToSubFromParent/verify`	0.02	0.00
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/FromSubToParent/verify`	0.01	0.00
`mfem/transfers/mfem_parent_mfem_sub.MFEMCopyTransfer/ComplexFromSubToParent/verify`	0.01	0.00
`mfem/transfers/mfem_sub_mfem_sub.MFEMCopyTransfer/error`	SKIP	0.00

Modules test summary

Compared against 953c577 in job civet.inl.gov/job/3779372.

No change

…espace (idaholab#32315)

loganharbour · 2026-05-01T03:12:41Z

The sweeps should be added to anything relating to transfers, meshing, or parallel algorithms.

This broke next: https://civet.inl.gov/event/292493/

…espace (idaholab#32315)

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch 2 times, most recently from 9d7807b to a2fc66d Compare February 18, 2026 14:24

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch 3 times, most recently from 5087a0c to 5ceba23 Compare February 24, 2026 09:37

GiudGiud assigned roystgnr Feb 24, 2026

alexanderianblair changed the title ~~WIP: Enable MultiApp transfers between MFEM and libMesh problems on CPU~~ Enable MultiApp transfers between MFEM and libMesh problems on CPU Feb 25, 2026

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from a256a01 to 791693c Compare February 25, 2026 16:25

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from a33274f to da45066 Compare February 25, 2026 19:54

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch 3 times, most recently from bcdd203 to 8c12ff0 Compare March 3, 2026 22:51

alexanderianblair marked this pull request as ready for review March 3, 2026 23:11

alexanderianblair requested review from lindsayad and nmnobre as code owners March 3, 2026 23:11

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from 8c12ff0 to 3057f8e Compare March 4, 2026 00:21

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch 2 times, most recently from 9f5bdad to 1dbcc43 Compare March 9, 2026 13:16

lindsayad reviewed Mar 11, 2026

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alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch 2 times, most recently from 08dd19f to 7f1c81f Compare March 12, 2026 17:45

moosebuild added the PR: Failed but allowed label Mar 12, 2026

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from 7f1c81f to e4c4583 Compare March 24, 2026 17:59

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alexanderianblair requested a review from lindsayad March 24, 2026 18:17

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from 1b3394d to c1f2cf7 Compare April 23, 2026 20:27

Use nqpt for consistency with MFEM, use make_range in MFEMMultiAppTra…

d5fab83

…nsfer loops, and fix docstrings

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from c1f2cf7 to d5fab83 Compare April 23, 2026 20:48

lindsayad approved these changes Apr 23, 2026

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Clean up outputs in tests/mfem/transfers/sibling_transfers test direc…

d6febef

…tory

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from e82400e to d6febef Compare April 24, 2026 01:30

alexanderianblair mentioned this pull request Apr 24, 2026

N->M MFEM MultiApp Transfers #32828

Open

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch 2 times, most recently from 17ee24c to 4d11729 Compare April 24, 2026 12:32

Simplify gather and action functors in MultiApplibMeshToMFEMShapeEval…

25b8962

…uationTransfer and add 1-to-N test

alexanderianblair force-pushed the alexanderianblair/mfem-to-libmesh-transfers branch from 4d11729 to 25b8962 Compare April 24, 2026 14:32

nmnobre requested changes Apr 28, 2026

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Comment thread framework/doc/content/source/mfem/transfers/MultiAppMFEMTolibMeshShapeEvaluationTransfer.md Outdated

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Comment thread framework/doc/content/source/mfem/transfers/MultiApplibMeshToMFEMShapeEvaluationTransfer.md Outdated

alexanderianblair and others added 2 commits April 29, 2026 01:52

Apply suggestions from code review

bdb8209

Co-authored-by: Nuno Nobre <nuno.nobre@stfc.ac.uk>

Revert change to square.e mesh, and rename square_quad.e mesh to squa…

58a80e6

…re_quad9.e

nmnobre approved these changes Apr 29, 2026

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nmnobre merged commit de74ae5 into idaholab:next Apr 29, 2026
68 of 69 checks passed

nmnobre added a commit to nmnobre/moose that referenced this pull request Apr 30, 2026

Fix docs for MultiAppMFEMShapeEvaluationTransfer and rm trailing whit…

c5b8349

…espace (idaholab#32315)

nmnobre added a commit to nmnobre/moose that referenced this pull request Apr 30, 2026

Adjust square and cube mesh names (idaholab#32315)

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nmnobre added a commit to nmnobre/moose that referenced this pull request May 3, 2026

Fix docs for MultiAppMFEMShapeEvaluationTransfer and rm trailing whit…

495dba9

…espace (idaholab#32315)

nmnobre added a commit to nmnobre/moose that referenced this pull request May 3, 2026

Adjust square and cube mesh names (idaholab#32315)

d1422a8

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