4.0 KiB
One measured-strain refinement example
Research only: one completed base-time observation, one possible growth-only fluid L2 enlargement, then two more base steps. L0/L1 and the Circle-containing L2 rectangle stay fixed. No scheduler, coarsening, packing, CUDA changes, or claim of accuracy, stable long-time adaptation, or optimal mesh selection.
The periodic initial shear wave is evolved for two base steps. The downloaded postcollision G moments supply actual L1 velocity, at dx=.5 and the parent's physical origin. The tagger measures |S|=sqrt(2 S:S), not vorticity. We use s*=|S|/0.05, cutoff .001, no wall band/history/buffer. This deliberately small cutoff exercises the mechanism; it is not an error estimator or calibrated physical criterion. A high cutoff yields no change with the same observation.
The eligible corridor is L1 indices [72,76) x [20,36), immediately right of the fluid child. Only L1 fluid leaves are valid gradient donors and owned voters; covered cells, holes and ghosts cannot supply gradients. L1 has no physical solid cells: the Circle is entirely in the fixed L2 patch. The cropped sparse arrays are never treated as a full periodic domain. One-sided derivatives may be used at missing-neighbor edges. Unknown gradients, unavailable corridor cells, and tags outside the corridor are reported separately. Ignored tags do not certify adequate resolution elsewhere. Old coverage is always retained.
grow_rectangle knows only a rectangle, boolean requests, alignment and area
cap. It returns an unchanged/enlarged tuple or raises ValueError before any
solver mutation. The caller validates the entire proposed mesh with the
existing RemapTopology and sparse-layout guards; remap_child repeats its full
runtime checks. This example targets exactly the original mesh once, not a
reusable adaptation loop. A rejection propagates explicitly; no partial
proposal is installed. All solver instances are independently closed.
Run
From repository root, with dependencies already available:
PYTHONPATH=src:. python -m unittest discover -s tests/unit -p test_shear_refinement_example.py -v
Only on an approved idle CUDA device:
PYTHONPATH=src:. python -m research.shear_refinement.example
PYTHONPATH=src:.:tests/validation/multigrid python -m unittest discover -s tests/validation/multigrid -p test_shear_refinement_example_gpu.py -v
The GPU gate compares automatic selection to an explicitly identical manual rectangle after short continuation, requires finite leaves, exact NaN masks, and an unchanged source. It does not replace independent numerical replay. GPU execution has not been performed in the implementation cloud environment.
Tagger provenance and license
boundary_shear_tagging.py is the unchanged accepted Grok standalone v0.2
preparation (2026-10-16), SHA256
12bc70ab989953501a752a2dc23e3712b6e69bfd47e67664c1771ff2dfa4da0b.
The delivered README_boundary_shear_tagging_v0.2.md identifies it as original
code under MIT, the same license as CelerisLab (see repository LICENSE), with
nothing copied from upstream examples. Its source ledger/review is in the
preparation/grok_amr_review/v0.2 handoff. Vendoring keeps this example runnable
without external preparation paths; it is not installed as production API.
The separate reviewed level-request policy v0.2.1 is intentionally not copied:
this example observes only L1 and can request only the existing L2 level.
Local implementation checks (2026-10-16)
Seven focused example tests passed. The combined CPU suite below passed all 60 tests, including existing topology, pinned-body and synchronized remap gates:
PYTHONPATH=src:. python -m unittest tests.unit.test_refinement tests.unit.test_refinement_three_level_multipatch tests.unit.test_pinned_body_remap tests.unit.test_runtime_child_remap tests.unit.test_synchronized_remap tests.unit.test_shear_refinement_example -q
Broad unit discovery was also attempted; 14 legacy module imports failed because PyCUDA is absent. That broad run is not a pass. No installation or GPU execution was attempted. The example uses a passive Circle, with no Jet drive.