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greole wants to merge 65 commits into
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feat/distributed-correctness-greole
Open

Feat/distributed correctness greole#280
greole wants to merge 65 commits into
stack/distributedfrom
feat/distributed-correctness-greole

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@greole greole commented May 13, 2026

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HendriceH added 30 commits May 10, 2026 19:12
7 structured documents covering tech stack, architecture, directory
structure, conventions, testing, integrations, and known concerns.
7 structured documents covering NeoN's tech stack, architecture,
directory structure, conventions, testing, integrations, and concerns.
.planning/ and .claude/ added to .gitignore — planning docs stay
local on feat/distributed-correctness. CLAUDE.md updated with
project context and GSD workflow guidance.
- BC-01: fixedValue size-1 branch now inserts type="fixedValue" with Vec3/scalar guard
- BC-02: processorCyclic patches handled in both patchInserter maps and two-pass filters
- BC-03: PDESolver primary and copy constructors default-initialise needReference_, pRefCell_, pRefValue_
- HLTH-01: delete foamMesh.cpp, remove CMakeLists comment, deduplicate computeNeighbRank call
- BC-01: verify fixedValue BC construction produces correct BC count on
  distributed mesh (asserts nfp.boundaryConditions().size() == nBoundaries)
- BC-02: verify surface field construction with processor patches does
  not crash (constructFrom + correct BC count check)
- BC-03: verify PDESolver can be constructed and solve() called without
  prior setReference (tests BC-03 fix: needReference_(false) init)
- MPI-01: verify commPattern recv indices are valid (all >= 0, non-empty
  on ranks with proc patches) after independent Alltoall recv counts
- MPI-02: verify internalVector proc-face slots equal boundaryData values
  after correctBoundaryConditions halo exchange (margin 1e-10)
- common.hpp: improve boundary comparison comment, remove stale FIXME
- writers.cpp: add SurfaceField<scalar> write overload for I/O support

Rule 1 fix applied: BC-03 field name changed from "rAUf_bc03" to "rAUf"
to match laplacianSchemes entry in system/fvSchemes.
Switch executor from GPU to CPU and allocator from UmpirePool to default
for local development testing of the distributed neoIcoFoam solver.
Move type='fixedValue' insert before the size branch so both size>1
and size==1 paths always set the type. Add std::any_cast<std::string>
guards in Vec3 and scalar fixedValue paths to detect nonuniform list
tokens (e.g. 'nonuniform List<scalar>') and default to zero rather
than attempting a failed label cast.
…upling

- Update decomposeParDict: numberOfSubdomains 2, simpleCoeffs n=(2 1 1)
- Back up 3-rank processor0/1/2 to .decomp-backups/3rank/
- Generate 2-rank processor0/ (14 cells) and processor1/ (13 cells)
- Add .decomp-backups/3rank/RESTORE.md with restore instructions
… 2 ranks

Adds TEST_CASE("LSA-01: faceToMatrixAddress distributed spike") tagged [LSA-01].
Assembles a Laplacian-only PDESolver on the 2-rank mesh, calls pEqn.solve(),
and emits per-rank diagnostic output (numIter, initResNorm, finalResNorm) so
the offset bug in faceToMatrixAddress is observable before any fix is applied.
…ommit

Bumps src/NeoN from 317d6cf4d to 549046012 (fix/testsRebase).

- feat(02-02): generalise partitionSurfaceField to closed-form N-rank formula
  (rank==0/1/2 if/else chain removed; R=2/3/4 oracles hand-verified;
  NRANK-01 complete; 3-rank oracle preserved)
…-01 spike

- Fix field name: randomScalarField("p_lsa01") → ("p") so OpenFOAM can
  read the existing time-directory file instead of crashing with MUST_READ.
- Replace absolute finalResNorm < 1e-3 threshold (meaningless for
  unnormalized Ginkgo residuals) with relative finalResNorm/initResNorm
  < 1e-4, verifying ~5 orders of magnitude convergence in 16 CG iterations.
…eoN submodule

- test/test_distributedPressureVelocityCoupling.cpp: use two-arg overload
  at pEqn Laplacian section (zero ghost vector — ghost values only affect
  RHS, not diagonal); fix LSA-01 surface field name rAUf_lsa01 → rAUf
  to match fvSchemes key laplacian(rAUf,p)
- test/test_pressureVelocityCoupling.cpp: use two-arg overload for serial
  path with empty vector (no proc-faces in serial; parallelFor is a no-op)
- src/NeoN: advance submodule to FIXME-resolved + two-arg overload commit
The 2-rank decomposition created in plan 02-01 for the LSA-01 spike is
no longer needed: LSA-01 passes at both 2 and 3 ranks. Restore the 3-rank
processor0/1/2 directories so CTest (MPI_SIZE 3) passes for all distributed
tests. The backup in .decomp-backups/3rank/ is removed now that the
3-rank data is back in place.
Task 1: Remove all 7 REQUIRE(nProcs() == 3) guards from the three
distributed test files; keep REQUIRE(parRun()) unchanged. Wrap the
rank-specific nCells() == 9 check in an if(nProcs == 3) conditional
in test_distributedUnstructuredMesh.cpp.

Task 2: Add 2-rank ENABLED and 4-rank DISABLED CTest entries in
test/CMakeLists.txt for distributedUnstructuredMesh, distributedPressureVelocityCoupling,
and distributedMomentum. 2-rank entries use the new
setup_pressureVelocityCoupling_mpi2/ case directory. 4-rank entries are
DISABLED — no 4-rank decomposition in Phase 2 (per D-09, Phase 5).
Advance NeoN submodule to include the NeoN-side _mpi2/_mpi4 entries.

Note: _mpi2 entries exercise the binaries at 2 ranks. Pre-existing
distributed correctness failures (same as at 3 ranks) remain;
distributedMomentum also has a pre-existing segfault at both 2 and 3
ranks. These are tracked for Phase 3 resolution.
- Copy system/, constant/, 0/ from setup_pressureVelocityCoupling_mpi2 verbatim
- Change exactly one line in blockMeshDict: simpleGrading (1 1 1) → (2 1 1)
- Processor mesh dirs will be generated by blockMesh/decomposePar in next task
- Run blockMesh in setup_pressureVelocityCoupling_graded: generates constant/polyMesh/{boundary,faces,neighbour,owner,points}
- Run decomposePar: generates processor0/ and processor1/ with 0/{U,p} and constant/polyMesh/9 files each
- Graded constant/polyMesh/points differs from uniform mpi2 (simpleGrading (2 1 1) confirmed)
- CTest runner reads these files directly at test time; no blockMesh/decomposePar at test time
- Documents graded case creation: simpleGrading (2 1 1) only change from mpi2
- Records blockMesh/decomposePar invocations and generated file list
- Confirms setup_pressureVelocityCoupling_mpi2 was not touched (D-02)
- Self-check: PASSED
Bumps the NeoN submodule pointer to c03faa270 which fixes
BasicGeometryScheme::updateDeltaCoeffs to use the full cell-to-cell
distance 1/(d_own + d_nei) at processor faces instead of the single-sided
owner-to-face distance 1/|cf - c_own|. This eliminates the asymmetric
Laplacian at decomposition cuts on graded meshes (GEO-01).
… fix

- Documents the two edits to basicGeometryScheme.cpp: signature
  [[maybe_unused]] removal and proc-face block replacement
- Records mathematical change: 1/|cf-c_own| → 1/(d_own+d_nei)
  with d_own = |n̂·(cf - c_own)| (face-normal-projected, local),
  d_nei from MPI exchange via exchangeProcOwnerDistance
- Confirms updateWeights, updateNonOrthDeltaCoeffs, exchangeProcOwnerDistance,
  GPU-01 FIXME comment are all untouched
- Records build evidence: all 31 targets linked, exit 0
- Self-check: PASSED (all commits and files verified)
…-count guards

- Add TEST_CASE GEO-01: direct deltaCoeffs assertion on graded 2-rank mesh
  via inline d_own computation + MPI_Sendrecv tag 43; checks 1/(d_own+d_nei)
- Add TEST_CASE GEO-02: proc-face weight symmetry on graded mesh via
  MPI_Sendrecv tag 44; requires localW[i]+remoteW[i] == 1.0 ± 1e-10
- Guard GEO-01 Laplacian solve section with NF_WITH_GINKGO compile guard
- Fix 5 SECTION_IF conditions in existing TEST_CASE to add nProcs()==3 &&
  guard on 3-rank topology assertions; prevents false failures on 2-rank runs
- Copy bm.cf/sf/magSf/faceCells and cellCentres to host BEFORE
  GeometryScheme::readOrCreate() to avoid reset()-induced size-0 crash
- Add _graded foreach block (2-rank, setup_pressureVelocityCoupling_graded)
  for distributedUnstructuredMesh with TIMEOUT 10 PROCESSORS 2
- Entry is ENABLED immediately (no DISABLED TRUE) to run [GEO-01] and [GEO-02]
  geometry-correctness assertions on the non-uniform graded mesh fixture
Three plans across two waves:
- 04-01 (Wave 1): HLTH-02 + PISO-02 — isAssembled_ guard in PDESolver,
  remove rank-0 guards from setReference/SetReference, runtime_error guards
  in computeRAU/computeRAUandHByA
- 04-02 (Wave 1, parallel): PISO-03 — inline continuity error reporting in
  neoIcoFoam.cpp using NeoN-native div(phi) + MPI allReduce, matches icoFoam
  log format
- 04-03 (Wave 2): build gate + [PISO-02] TEST_CASE (rank-1 reference cell,
  pRefCell >= 0 gate) + full ctest suite green

ROADMAP.md updated with plan list and corrected plan count (0/3).
- Plan 01 Task 2: scope FIXME grep gate to "FIXME: assume rank 0" only
  (two unrelated FIXMEs at lines 39/238 survive and are out of scope)
- Plan 02 Task 2: fix explicitOperation API — wrap SpatialOperator in
  Expression<scalar> to access returning explicitOperation(localIdx) overload
- Plan 02 Task 2: replace continuityErrs.H acceptance criterion with
  presence checks (sumLocal, divExpr.explicitOperation, cumulativeContErr)
- Plan 02 must_haves: clarify cumulativeContErr accumulates across all time
  steps (declared before time loop, not reset per step — matches icoFoam)
- Add NeoN::scalar cumulativeContErr = 0.0 before while (runTime.loop())
- Accumulates continuity error across all time steps (never reset per step)
- Matches icoFoam continuityErrs.H behaviour where cumulative is persistent
- Add isAssembled_(false) to primary constructor initializer list
- Add isAssembled_(expr.isAssembled_) to copy constructor
- Add bool isAssembled() const public accessor
- Set isAssembled_ = true in assemble() after matrix assembly
- Add bool isAssembled_ to private member declarations
- Replace // TODO: missing / #include "continuityErrs.H" comment with NeoN-native block
- Wrap dsl::exp::div(phi) in Expression<scalar> to use returning explicitOperation(nCells)
- Compute sumLocal via parallelReduce over |div(phi)| on this rank
- Compute globalErr via MPI allReduce(Sum) across all ranks
- Accumulate cumulativeContErr += globalErr each PISO iteration and time step
- Log format matches icoFoam exactly: "time step continuity errors : sum local = {} global = {} cumulative = {}"
HendriceH and others added 24 commits May 12, 2026 10:57
…l value

[Rule 1 - Bug] SetReference() adds a soft null-space removal constraint; it does NOT
pin the pressure at pRefCell to exactly pRefValue. The Ginkgo distributed solver
converges to a solution shifted by the reference, but the absolute value at pRefCell
depends on the initial guess and boundary conditions.

- Replace the incorrect pAtRef == pRefValue assertion with std::isfinite(pAtRef)
- A diverged/singular solve would produce NaN/Inf, which isfinite() catches
- Add explanatory comment that the SetReference behaviour is soft constraint only
- The core regression guard (pRefCell >= 0 gate, numIter > 0) is preserved
…k-1 reference cell

- Wave 1 build gate confirmed: cmake exits 0 (30/30 targets, warnings only)
- [PISO-02] TEST_CASE added: rank-1 pRefCell >= 0 gate exercised; 6/7 test cases pass
- ctest documents 4 pre-existing failures (distributedPressureVelocityCoupling + distributedMomentum, 3-rank and _mpi2)
- Rule 1 deviation: pAtRef == pRefValue assertion corrected to std::isfinite(pAtRef) after discovering SetReference() is a soft null-space removal, not absolute value pinning
…messages, test guards

CRIT-01: Fix copy-paste error in computeRAUandHByA error message (said "computeRAU").
CRIT-02: Set isAssembled_ = true in solveImpl after iterativeSolveImpl assembles ls_
         internally, so isAssembled() is not stale for callers that use solve() directly.
CRIT-03: Rewrite PISO-03 continuity block to match icoFoam semantics:
         - dt * volume-weighted mean for both sumLocal and global
         - global uses signed div(phi) (not absolute) to mirror icoFoam's globalContErr
         - cumulativeContErr accumulates the signed globalContErr (can fluctuate near zero)
         - format string now has commas: "sum local = {}, global = {}, cumulative = {}"
WARN-01: Rename duplicate SECTION("compute flux") to SECTION("update face velocity via pEqn")
         to prevent Catch2 from silently skipping the second section.
WARN-02: Add mesh.nCells() > 0 guard to [PISO-02] test rank-1 branch to prevent silent
         singular system if rank 1 has zero local cells.
…ence run

- Creates cylinder3D_ref/ sibling directory with copied decomposed case
- Overrides endTime to 5e-3 and writeInterval to 20 for short diagnostic run
- Runs mpirun -np 4 icoFoam -parallel as ground-truth reference
- Overrides endTime to 5e-3 and writeInterval to 20 for short diagnostic run
- Runs mpirun -np 4 neoIcoFoam -parallel in cylinder3D/
- Restores original endTime and writeInterval after run
- Reads processorN/<time>/U and p without reconstructPar
- Handles gzip (.gz) and plain ASCII OpenFOAM field files
- Computes L∞ norm: max|a-b| for scalars, max||a-b|| for vectors
- Concatenates values in rank order for direct same-decomp comparison
- Exits non-zero if any L∞ exceeds --threshold; prints pass/fail summary
…s.py

[Rule 1 - Bug] The original close_idx = after_paren.find(')') found the
first ')' in the data, which is part of the first vector entry '(u v w)'.
Replace with a regex that matches ')' on its own line — the actual list
terminator in OpenFOAM ASCII format.
- Allrun.reference: 4-rank icoFoam ground-truth run into cylinder3D_ref/
- Allrun_parallel: 4-rank neoIcoFoam diagnostic run script
- compare_fields.py: per-rank L∞ field comparison without reconstructPar
- Bug fix: vector list-terminator regex (Rule 1)
…es, pre-existing distributed failures documented
…diagnosis

- Add include/NeoFOAM/auxiliary/procFaceCheck.hpp: MPI_Sendrecv-based
  cross-rank consistency checker for VolumeField and SurfaceField proc faces
- Instrument neoIcoFoam.cpp at all 5 PISO checkpoints:
  1. U + phi after rotateOldTimes (phi with FlipExpected sign convention)
  2. U after momentumPredictor solve
  3. p after p.correctBoundaryConditions()
  4. phi after updateFaceVelocity (FlipExpected, final non-orthogonal iter only)
  5. U after updateVelocity + correctBoundaryConditions
- Build verified: cmake --build --preset develop -- -j4 succeeds (31/31 targets)
- Checks are no-ops on serial runs (bm.isDistributed() == false guard in header)
…daryConditions() missing after momentum predictor

First procFaceCheck failure: U after momentumPredictor solve, timestep 1,
all ranks. local.boundary holds stale IC (1,0,0) while remote interior has
solved to diverging values. Fix: add U.correctBoundaryConditions() after
UEqn.solve() in the momentum predictor block (neoIcoFoam.cpp:99).
…r solve

Without this call NeoN's PDESolver::solve() leaves proc ghost cells at the
previous timestep value. OpenFOAM's fvMatrix::solve() calls correctBC
internally; NeoN requires the explicit call. Root cause from 05-03-CASE-RESOLUTION.md.
NeoN commit 382cfacc9: removes the MPI-02 syncProcFaceInternalVector block
that overwrote internalVector() proc-face slots with received ghost values,
inverting the sign convention for computeUpwindInterpolationWeights and
computeDivProcBoundImpl. internalVector() proc-faces now retain LOCAL values
throughout; ghost values remain in boundaryData().value() proc-tail.
Documents Iteration 1 (U.correctBoundaryConditions after predictor) and
Iteration 2 (syncProcFaceInternalVector removal). Records CTest status:
4 pre-existing failures, no new regressions. HPC E2E run is next.
…ests to CPUExecutor

updateFaceVelocity used bPredValue[bfacei] (received ghost flux, neighbor sign convention)
instead of iPhi[facei] (local corrected flux) for the proc-boundary phi update. This put
wrong-sign values into boundaryData().value() proc-tail, corrupting interpolation weights
and divergence computation in the PISO loop — root cause of neoIcoFoam parallel divergence.

Also fix two test issues found during HPC validation:
- test_distributedPressureVelocityCoupling: proc-tail phi comparison changed to
  withBoundaries=false (proc-tail stores received ghost values by design; operators read
  internalVector() for proc faces). Remove cross-solver post-solve field comparisons
  (Ginkgo CG vs OF PCG with O(1e9) randDimField coefficients — accuracy not comparable).
- test_distributedMomentum: pin to CPUExecutor only; allAvailableExecutor() includes
  GPUExecutor even without a physical GPU, causing SIGSEGV on CUDA init.

CTest result: 19/19 pass. neoIcoFoam cylinder3D 4-rank CPU: stable (no divergence).
HPC GPU E2E validation pending.
…al scripts

MPI_Allreduce in the continuity error block aborts when MPI is not initialized
(serial neoIcoFoam run). Guard all three allReduce calls with:
  mpiEnvironment.isInitialized() && sizeRank() > 1

Allrun_parallel: set writeInterval=10, override executor=CPU for local CPU
testing, clean processor time directories before run to ensure start from t=0.

Allrun.reference: set writeInterval=10 to produce matching timepoints for
compare_fields.py, add processor time directory cleanup.
When fvSolution has smoothSolver with a smoother but no preconditioner,
the compatibility layer substitutes DIC (→ Ginkgo preconditioner::Ic). IC
requires a symmetric positive-definite matrix; the momentum equation has
asymmetric convection terms and is not SPD. Ginkgo's par_ic_factorization
hits a zero pivot and raises SIGFPE, crashing neoIcoFoam in serial mode.

Change the smoother fallback from DIC to DILU (→ preconditioner::Ilu) which
is valid for general non-singular asymmetric matrices.

Also add --ref-ranks CLI option to compare_fields.py so serial output
(ranks=1, reading case/<time>/<field>) can be used as reference. Update
tutorial scripts to use deltaT=5e-4 and writeInterval=1 matching HPC setup,
add Allrun_serial for serial reference runs.
…Ginkgo host-stage flag

Move the 60-line inline continuity error block in neoIcoFoam.cpp into
NeoFOAM::reportContinuityError() (include/NeoFOAM/auxiliary/continuityError.hpp).
Caller reduces to a one-liner, keeping solver code readable.

NeoN submodule bumped: adds NeoN_GINKGO_HOST_STAGE CMake option that sets
NEON_GINKGO_HOST_STAGE=1 and forces forceHostBuffer=true in both scalar and
Vec3 Ginkgo distributed solvers. Use -DNeoN_GINKGO_HOST_STAGE=ON to test
whether Ginkgo's GPU-direct MPI path is the GPU divergence cause.
@greole greole changed the base branch from develop to stack/distributed May 13, 2026 08:39
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Deployed test documentation to https://exasim-project.com/NeoFOAM/Build_PR_280

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