global_evaluate: faithful parallel evaluate() (fix out-of-domain mislocation)#222
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lmoresi merged 3 commits intoJun 12, 2026
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…location global_evaluate's parallel path had no correct handling for query points outside the (old) domain: the evaluation-swarm migrate routes unclaimed points by nearest rank centre-of-mass and strands them on an arbitrary rank, which then extrapolates from a geometrically-far cell -> silently-wrong values, parallel-only (e.g. an annulus boundary point reading the opposite side). This corrupted mesh-variable transfer on parallel mover-adapted meshes. Restore the serial evaluate() contract (interpolate inside / extrapolate from the TRUE nearest cell outside / flag inside-outside) with a best-claim out-of-domain fallback in global_evaluate_nd: allgather the (small, boundary-layer) extrapolated set; every rank reports its nearest-local-cell distance + its LOCAL rbf extrapolation; Allreduce(MIN dist / MIN rank / SUM winner value) picks the globally-nearest rank's value. Only unconditional collectives + local rbf_evaluate (never the collective FE interpolation, which would desync) -> deadlock-safe. O(boundary points), no dense global tree. Default on; GE_LOCAL_FALLBACK=0 restores legacy. Serial unchanged (gated mpi.size>1). Validated: deterministic-rotation gate, linear field T=x, np=5, max_err 1.06 -> 0.003 (== serial). Underworld development team with AI support from Claude Code
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Pull request overview
This PR updates global_evaluate_nd to correct MPI-parallel evaluation for points that end up outside any rank’s owned cells after the swarm migrate round-trip, aiming to make parallel behavior match the serial evaluate() contract (interpolate in-domain; extrapolate just outside; return inside/outside via check_extrapolated) and to avoid deadlocks by using only unconditional collectives and rank-local RBF evaluation.
Changes:
- Adds a parallel “best-claim” out-of-domain fallback: allgather stranded points, compute per-rank distance/value, and Allreduce to select the globally-best rank’s extrapolation.
- Adds an environment-variable escape hatch (
GE_LOCAL_FALLBACK) to disable the new fallback and restore legacy behavior. - Expands the
global_evaluate_nddocstring/comments to document the parallel contract and deadlock-safety constraints.
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| ext_vals, ext_flag = evaluate_nd( | ||
| expr, all_ext, rbf=True, evalf=False, verbose=False, | ||
| check_extrapolated=True,) | ||
| ext_vals = np.ascontiguousarray( | ||
| np.asarray(ext_vals, dtype=np.double).reshape((n_ext_total,) + expr_shape)) | ||
| ext_flag = np.asarray(ext_flag).reshape(n_ext_total).astype(np.int32) | ||
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| # Nearest-local-cell distance for every point (local kd-tree query). | ||
| mesh._build_kd_tree_index() | ||
| dist2, _ = mesh._centroid_index.query(all_ext, k=1, sqr_dists=True) | ||
| dist2 = np.ascontiguousarray(np.asarray(dist2, dtype=np.double).ravel()) |
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| import os | ||
| if uw.mpi.size > 1 and os.environ.get("GE_LOCAL_FALLBACK", "1") not in ( | ||
| "0", "off", "false", "no", ""): |
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| Contract: this is a faithful *parallel* counterpart of :func:`evaluate` — | ||
| a query point is interpolated wherever in the mesh it lands (on any rank), | ||
| a point just outside the mesh is extrapolated from its true nearest cell, | ||
| and ``check_extrapolated`` returns an inside/outside flag per point. The |
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| # ------------------------------------------------------------------ | ||
| # Out-of-domain extrapolation — keep the parallel result a faithful | ||
| # match for the serial ``evaluate()`` contract: interpolate a point | ||
| # wherever it lands across ranks, extrapolate a point just outside the | ||
| # mesh, and flag inside/outside. |
…K env) The parallel out-of-domain best-claim fallback was controlled only by the GE_LOCAL_FALLBACK environment variable (Copilot review flag). Promote it to a real local_fallback=True kwarg threaded through global_evaluate -> _global_evaluate_impl -> global_evaluate_nd. The kwarg is the supported control surface; the env var, if explicitly set, still overrides it — an operator escape hatch retained because of the parallel-deadlock debugging history (a no-code kill switch for the added collectives). Serial is untouched and bit-identical regardless of the kwarg. Underworld development team with AI support from Claude Code
- GE_LOCAL_FALLBACK parsing is now case/whitespace-insensitive (.strip().lower()), so False/OFF/No disable the fallback as expected. - clarify the contract docstring: out-of-domain points extrapolate from the globally nearest cell by a centroid-distance heuristic (lowest rank wins ties), not necessarily the exact nearest cell. Underworld development team with AI support from Claude Code
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Pushed fixes for the review nits:
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…og, value-first call-site sweep (WE-01..03,05,06,08,09,10) (#338) * docs(WE-01): adopt the one-governing-doc-per-topic authority map Repoint CLAUDE.md's Data Access 'Authoritative Reference' from the stale UW3_Style_and_Patterns_Guide.md to subsystems/data-access.md (the guide it crowned teaches patterns the code deprecates at runtime — DOC-04), and record the Style Charter §10 authority table in docs/developer/index.md as the master authority index. The Charter is added to the Getting Started toctree (removes a baseline 'not included in any toctree' warning). Finding: DOC-04 (docs/reviews/2026-07/DOCS-STANDARDS-COHERENCE.md). Underworld development team with AI support from Claude Code * docs(WE-02): de-drift the Style Guide's four stale normative sections Rewrites the sections DOC-01 verified as contradicting the settled standards: - Docstring format: the 'Markdown Docstrings for pdoc/pdoc3' section is replaced by the NumPy/Sphinx RST standard (worked example with :math: and Parameters/Returns/Examples/Notes; conversion tracked in docs/plans/docstring-conversion-plan.md), per Style Charter section 6. - Doc file format: Quarto .qmd prescription (zero .qmd files exist in the repo) replaced by MyST .md/Sphinx guidance matching CLAUDE.md; migration table row updated. - Data access examples: 'Preferred' coordinate examples now use the real, runnable API — mesh.X.coords (read), mesh.deform() (coordinate changes), and the swarm.coords getter/setter for particle positions. The previous 'Preferred' example swarm.data += displacement raises AttributeError (getter-only property — SWARM-13 evidence); mesh.data warns at runtime. The private-attribute migration advice (swarm._particle_coordinates, mesh._deform_mesh presented as the NEW pattern) is deleted. - Front matter: the 21-line Quarto YAML header is replaced by a minimal MyST title block, and the guide now states that the UW3 Style Charter is the normative contract and wins on conflict. All replacement examples verified against current source: Swarm.coords setter (swarm.py), Mesh.deform (discretisation_mesh.py:3133), uw.synchronised_array_update / NDArray_With_Callback.delay_callbacks_global. Findings: DOC-01, SWARM-13 (style-guide part). Underworld development team with AI support from Claude Code * docs(WE-03): regenerate the docstring review queue; add the sweep to the release checklist The queue (last generated 2026-01-13, cdf5bb2) misrepresented the codebase both ways: it flagged now-complete items (solve, SNES_Scalar) as missing and contained zero entries for the June 2026 API (DOC-02). Regenerated over src/underworld3/**/*.py + **/*.pyx at the current tip. Two bugs in scripts/docstring_sweep.py's regex-based Cython parser made the regenerated queue lie about .pyx docstrings and are fixed as part of making the regeneration meaningful: - the indent group '(\s*)' with re.MULTILINE consumed preceding blank lines, shifting the computed definition line so the docstring search started ON the def/class line and always missed; - the docstring search started at the definition line rather than after the (possibly multi-line) signature, so long signatures hid their docstrings; - raw-string docstrings (r""", the norm in the solver .pyx) were not recognised. DOC-02 cross-validation on the regenerated queue now passes: solve / SNES_Scalar in the solver pyx are no longer flagged 'none'; the queue contains the June API (add_nitsche_bc, add_rotated_freeslip_bc, boundary_flux, set_custom_fmg, consistent_jacobian: 13 mentions) and flags the DOC-05 targets (Swarm.advection x2, read_timestep, write_proxy) as undocumented. Also adds the sweep to the quarterly release checklist (guides/release-process.md) so the queue cannot go stale unnoticed again. Findings: DOC-02 (docs/reviews/2026-07/DOCS-STANDARDS-COHERENCE.md). Underworld development team with AI support from Claude Code * docs(WE-05): backfill the changelog for May - early July 2026; add the changelog sweep to the release checklist The changelog (the quarterly CIG/stakeholder record) ended in April 2026 while ~117 first-parent commits landed May through early July (DOC-03). Backfilled at the existing conceptual granularity — 14 grouped entries, grouped by subsystem rather than by PR, matching the established format (### Title (Month Year), bold lead sentence, hyphen bullets, inline PR references): - New '2026 Q3 (July - September)' section: the July 2026 quality campaign (#309-#313, #317, #322-#326, #329, #334 as grouped entries), rotated strong free-slip / boundary traction / dynamic topography (#293, #294, #298, #306), generalized geometric multigrid via custom prolongation (#290, #297), consistent Jacobian tangent (#258), swarm correctness (#216, #313, #323, #329), numpy 2 support (#301, #305). - Extended '2026 Q2' section with the May-June entries: mesh adaptation movers (#190, #209, #213, #228, #259, #264, #266), moving-mesh field transfer / deform() (#246, #249, #251), semi-Lagrangian accuracy controls (#164, #183, #185-#189, #208, #220), snapshot/checkpoint toolkit (#146, #195, #196, #198), Stokes_Constrained (#224, #229, #240, #265), local-h Nitsche + boundary-slip surfaces (#225, #241, #275), units interoperability (#277, #278, #283, #284), memory/evaluation/solver infrastructure (#161, #177-#179, #181, #182, #222, #237, #250, ...). Every entry is backed by a merged commit on development (verified against git log --first-parent aed517f..3184a40). Also adds a quarterly-changelog sweep step beside the docstring sweep in the release checklist (guides/release-process.md) per DOC-03's proposed fix. Findings: DOC-03 (docs/reviews/2026-07/DOCS-STANDARDS-COHERENCE.md). Underworld development team with AI support from Claude Code * docs(WE-06): status headers on the unmarked design docs (per-doc git verification) Adds one-to-three-line Status markers to the 13 design docs that lacked one, following the directory's existing conventions (**Status**: line under the title; status: key inside existing YAML frontmatter for the three frontmatter-only docs), and corrects the stale 'Design Phase' marker on MATHEMATICAL_MIXIN_DESIGN.md (the mixin ships in utilities/mathematical_mixin.py). Every stamp was verified against git history (git log --follow dates) and the current source tree before writing: - Implemented: jacobian-consistent-tangent (PR #258, c63cd70), fmg-checkpoint-hierarchy (3cd73cd), petsc-dmplex-checkpoint-reload-plan (PR #146, write_timestep(petsc_reload=True) in tree), fault-refinement-simplification (smooth_mesh_interior / metric_density_from_gradient / fault_comb_metric all in tree), MATHEMATICAL_MIXIN_DESIGN. - Current reference/contract: mesh-adaptation-formulation, ND_UNITS_BOUNDARY_CONTRACT (PR #278, e0ece9a). - Investigation records (preserved via PR #245, 34a9dd4; production geometric-MG is custom prolongation, PR #290): snesfas-feasibility, snesfas-vanka-feasibility-study. - Design notes / prototypes with honest gaps: in_memory_checkpoint_design (not implemented, per its own trailing Status section), submesh-solver-architecture (extract_region/extract_surface exist; coarsened_companion does not). - Historical: ARCHITECTURE_ANALYSIS (persistence.py layout superseded), COORDINATE_MIGRATION_GUIDE (transition shipped), WHY_UNITS_NOT_DIMENSIONALITY (decision record). The audit's ~16 estimate over-counted: re-derived at this tip, 13 docs were unmarked plus one marked-but-stale (DOC-07). Findings: DOC-07 (docs/reviews/2026-07/DOCS-STANDARDS-COHERENCE.md). Underworld development team with AI support from Claude Code * docs(WE-08): convert units.py public docstrings Google -> NumPy style Docstring-only conversion of the 18 public module-level functions that carried Google-style Args:/Returns:/Raises:/Examples: labels (check_units_consistency, get_dimensionality, get_units, non_dimensionalise, show_nondimensional_form, simplify_units, create_quantity, convert_units, to_base_units, to_reduced_units, to_compact, get_scaling_coefficients, set_scaling_coefficients, validate_expression_units, assert_dimensionality, validate_coordinates_dimensionality, enforce_units_consistency, require_units_if_active, convert_angle_to_degrees) to the NumPy/Sphinx standard (Style Charter section 6). dimensionalise was already NumPy style; one-line docstrings and private helpers are untouched. No code, signature, or behaviour changes (verified: every diff hunk is inside a docstring; ast.parse clean). Finding: API-12 (docs/reviews/2026-07/API-CONSISTENCY-REVIEW.md). Underworld development team with AI support from Claude Code * docs(WE-09): sweep call sites of the newer BC methods to value-first (conds, boundary, ...) order Wave C (#334) made the ORIGINAL value-first order canonical for add_nitsche_bc / add_rotated_freeslip_bc / add_constraint_bc (maintainer decisions D2/D3; Style Charter section 6) with deprecation shims for the legacy boundary-first and g= spellings. This sweep updates every call site of those THREE methods to the canonical order so nothing in the repository exercises the shims — 74 sites total: - tests/: 63 call sites across 12 files (test_1017, test_1018, test_1060, test_1061, test_1062, test_1064, test_1065 x2 serial; parallel test_1017, test_1062, test_1063, test_1064). tests/test_0641_wave_c_api_shims.py is deliberately untouched — its legacy-order calls ARE the deprecation contract. - docs/: 7 sites (curved-boundary-conditions.md x4, CONSTRAINED_FREESLIP_MULTIPLIER.md call + signature line, examples/submesh_investigation/test_region_ds_nitsche.py). - .claude/skills/: 3 sites (adapt-on-top-faults x2, free-surface-convection x1). - CLAUDE.md: 1 signature reference (free-slip BC preference section). The ~1,370 legacy-trio (add_dirichlet_bc/add_natural_bc/add_essential_bc) sites already conform and are untouched per the D2 decision. The audit review documents under docs/reviews/2026-07/ record the pre-decision state as evidence and are not swept. Discovered while verifying the swept tests run warning-free: the Wave C zero-datum guard in add_rotated_freeslip_bc rejects FLOAT zero (sympy.sympify(0.0) != 0 is structurally True), so the canonical add_rotated_freeslip_bc(0.0, boundary) raises NotImplementedError while conds=0 works. Filed as issue #336 with a TODO(BUG) marker at the guard (comment-only src touch); the swept call sites use the working integer form add_rotated_freeslip_bc(0, boundary). No fix applied here (Charter section 9 scope discipline). Findings: API-01/API-02 sweep (WE-09, REMEDIATION-WORKLIST.md). Underworld development team with AI support from Claude Code
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Problem
global_evaluate's parallel path silently returned wrong values for query points outside the (old) domain. The evaluation-swarmmigrateroutes unclaimed points by nearest rank centre-of-mass and strands them on an arbitrary rank, which extrapolates from a geometrically-far local cell. Deterministic reproduction (rotation gate, linear fieldT=x, np=5): a point atx=+0.64read−0.42(opposite side),max_err=1.06. This corrupted mesh-variable transfer on parallel mover-adapted meshes.Fix
Make
global_evaluatea faithful parallelevaluate()— interpolate inside, extrapolate from the true nearest cell outside, flag inside/outside. A best-claim out-of-domain fallback inglobal_evaluate_nd:allgatherthe (small, boundary-layer) extrapolated set,Allreduce(MIN dist / MIN rank / SUM winner-value)picks the globally-nearest rank's value.Only unconditional collectives + a local
rbf_evaluate(never the collective FE interpolation, which would desync per-rank → hang). O(boundary points), no dense global tree. Deadlock-safe by construction.Default on;
GE_LOCAL_FALLBACK=0restores legacy. Serial path unchanged (gatedmpi.size>1).Validation
Rotation gate,
T=x, np=5:max_err 1.06 → 0.003(bit-identical to serial0.003); turning the fallback off reproduces1.06. tier-A green; used throughout the parallel adaptive-convection runs.Underworld development team with AI support from Claude Code