69 Commits

Include renames

Author	SHA1	Message	Date
Omar SobhandClaude Fable 5.1	172a26dee4	PERF-2 P0: intra-step profiler — StepTimers on the overset solver (RTX_PROFILE; overlap build / predictors / patch BiCGSTAB / background Poisson with its setup-vs-iterate split / round exchange / apply / end exchange), PoissonSolution carries setup_ns and iterate_ns, the harness times advance / restore / snapshot / load sampling / force / FEA predictor and prints the wall split of the coupled phase; no clock is read when profiling is off; the reclassified/step progress denominator fixed (was ×4) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01YJPeT6WA2e7YvAnS875AHL	2026-09-15 22:25:52 -05:00
Omar SobhandClaude Fable 5.1	96a7f1c700	rtx-cfd: Robin wall sign pin — a still closed annulus under a uniform pressure above a zero datum: the explicit offset recedes into the body at exactly −p₀/(α(1+g)) (3e-16), the implicit compliant term answers with a pressure DROP (mean 0.17 of p₀, max 0.36) that absorbs the recession (net wall flux 6e-19 of 0.51); the steady MMS pin is blind to the sign of both parts ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01YJPeT6WA2e7YvAnS875AHL	2026-09-15 11:17:38 -05:00
Omar SobhandClaude Fable 5.1	1c98156653	rtx-cfd: the deformed-tip outline chooses the flat / semicircle branch against the UNDEFORMED half-thickness — at the semicircle setting the deformed tip's radius breathes by nanometres and flipped the topology (143 → 144 points) within the first steps of the P6-b ny 41 cap-12 release at every α; pin: the point count is fixed under ± 1e-6 thickness breathing at h 10 / 6.6 mm and ny 41, semicircle and flat ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01YJPeT6WA2e7YvAnS875AHL	2026-09-15 11:13:55 -05:00
Omar SobhandClaude Fable 5.1	c3dbd5040a	P6-b design 2: the Robin wall on the patch's Inner side — RobinWall { alpha, datum } with the wall velocity u_s + (t_f − datum)/α (explicit, damped by the wall's own viscous gain μ/(α d)) and the compliant-wall pressure term |S| p'/α implicit in the projection (the added-mass operator in the fluid's own response); Dirichlet bit for bit when off; MMS pin on the skewed annulus (orders 2.46/2.13 at α = 10 and 100 μ/h, the Dirichlet values; a 1e12 wall reproduces Dirichlet to 2e-6); OversetPisoSolver::patch_mut; harness knob RTX_FSI2O_ROBIN_ALPHA with the previous pass's tractions as the datum, printed in the header ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01YJPeT6WA2e7YvAnS875AHL	2026-09-15 10:46:35 -05:00
Omar SobhandClaude Fable 5.1	415c32ab04	overset mesh: the flat-tip outline (P5-3 option B) — cylinder_flag_outline_deformed_tip / cylinder_flag_patch_deformed{,_from}_tip take the tip's corner radius (t = the recorded semicircle, bit for bit; smaller = the benchmark's flat face between corner arcs sampled at the wall spacing, point count fixed across the deformation, the tip's corners kept off the hull source); pins: corner t reproduces the recorded outline, the 2.5 mm outline has the exact area excess with no collapsed spacing, the O-grid builds straight and at ± 80 mm cold and warm at ny 41/62; harness knob RTX_FSI2O_TIP_CORNER (default 0.01) on the cold and warm builds, printed in both headers; pinned-toolchain fmt on touched crates ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01LzcjQX7tvgn87CQCyg9Cfr	2026-09-13 22:22:08 -05:00
Omar SobhandClaude Fable 5.1	754dcd3679	overset: the energy pin (P5-3) — the rigid cylinder + flag outline pitching about the cylinder's centre in still fluid on the moving patch at the FSI2 fluid and grid; per-cycle net fluid work on the body (must be ≤ 0 at every h), gross +/− split, and the last-two-period moment fit → added inertia + rotational damping; knobs RTX_OVERSET_NY / _EP_PERIODS / _EP_TIP / _EP_F; ny 41 one-period smoke: net −5.62 J/m, damping 56.9 N·m·s/m (π c θ0² ω = 5.6 J, self-consistent), 21 s ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01LzcjQX7tvgn87CQCyg9Cfr	2026-09-12 20:57:58 -05:00
Omar SobhandClaude Fable 5.1	914d369efe	overset: the stamp-energy instrument (P5-3's energy-source measurement) — OversetResult gains stamp_energy (½ρ(u_stamped² − u_before²)·dx·dy summed over the fringe faces after the flux balance on a reclassification step) and reclass_energy (the faces touching a cell whose class changed); the replay CSV logs both plus the reclassified-cell count per step — the comparator showed the plate loads per unit motion agree with ours to ~10 %, so the discrepancy is our limit-cycle amplitude, an h-growing energy source, and the hole boundary's reclassification is the candidate ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-12 17:32:05 -05:00
Omar SobhandClaude Fable 5.1	33534ee688	overset added-mass pin (P5-3): a no-slip cylinder on the moving patch oscillating in a closed box of still fluid, the force fitted over the last two periods — C_m = 1.069 (n = 32) / 1.097 (n = 64) against Stokes's 1.064 plus box blockage: the composite's unsteady pressure response is right, the FSI2 lift excess is not the unsteady term's scale ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-09 18:01:53 -07:00
Omar SobhandClaude Fable 5.1	3e019d1491	P5-3 instruments: per-region wall loads on saved instants (top / bottom / tip arc / fillets+cylinder — drag, lift, normal-traction mean/min/max; RTX_FSI2O_AUDIT_FACES, RTX_FSI2O_AUDIT_ONLY) and the patch-thickness knobs (RTX_FSI2O_PATCH_OFFSET / _PATCH_ROWS, RTX_OVERSET_PATCH_OFFSET / _PATCH_ROWS; save tags carry the offset) — the overlap band sat at a fixed number of cells (6 h) and moved inward in metres with refinement ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-08 05:35:14 -07:00
Omar SobhandClaude Fable 5.1	06229dd9a2	rtx-cfd: the deformed cylinder–flag build's hull source carries the deformed outline — the cylinder + tip disc alone give the chord under a bent flag's convex side (P5-2 died at tip −35 mm with the patch 4.4 h thick where 6 h was asked, an acceptor's donor on a prescribed face); the death reproduced from the last saved instant by extrapolating the interface (fsi2_overset_probe_death_from_instant, with the failing acceptor's ray geometry and the overlap depths that build) and gone with the fix at every τ; RTX_FSI2O_ROWS; the zero-displacement mesh gate at 1e-5 (the pipeline's), the outline gate 1e-12 unchanged ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 10:25:46 -07:00
Omar SobhandClaude Fable 5.1	3a68048934	rtx-cfd: cylinder_flag_patch_deformed_from — the warm-started regeneration (P5's cost lever): the previous patch's interior and its outer ring projected onto the new offset polygon as the start, and an IDEMPOTENT build (one Winslow sweep alternating with the ray re-spacing; the P4-0 one-shot is not a fixed point — measured as the interior moving 0.05 h per build at rest), so a base converged as that map's fixed point stays put (9e-11 h at rest) and each build tracks the outline (interior/wall motion 0.99–1.14, worst angle 74.7°, wall row 0.37 h) 4.5× faster than the cold build; the rigid generator untouched (pins pass); fsi2 overset harness: RTX_FSI2O_WARM_SWEEPS with the converged base as the initial patch and the committed step's mesh as each step's warm start ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 09:10:05 -07:00
Omar SobhandClaude Fable 5.1	2ed36c3a8c	P5-1 instruments: the overset fluid saves/loads its rigid-phase state (RTX_FSI2O_SAVE / _LOAD — a coupling experiment then costs seconds, not the 12-minute rigid march), dumps the interface edges when the composite refuses a patch (RTX_FSI2O_DUMP_DIR, at the advance where the overlap is rebuilt), the release time is the fluid's clock; patch_cylinder_flag_deformed: cells inside the flag are holes at small bends and both sweep counts (the cantilever shape does not reproduce the P5-1 death — the CSVs show a coupling runaway), and a dumped-edges reproduction test ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 08:09:56 -07:00
Omar SobhandClaude Fable 5.1	d74571e21a	rtx-cfd: the deformed cylinder–flag outline's edge fractions come from the UNDEFORMED straight edge (x_tip_ref), so the patch topology is the mesh family's and not the deformation's — the P5-1 gate run died at the first bend with set_mesh refusing 143 → 144 wall cells; the P5-0 test now gates ns across amplitudes (143 at −80 / +40 / +80 mm) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 07:34:26 -07:00
Omar SobhandClaude Fable 5.1	f0b2563bf8	P5-1: FSI2 with the fluid on the overset — fsi2_harness/overset.rs (the background without a body, the cylinder–flag patch regenerated around the deformed flag every pass via set_patch_mesh, the wall velocity from the interface velocities along the wetted polygon, the load from the patch's wall faces into WettedSurface::transfer_load — no probes, no clamp, no smoothing), fsi2_harness/overset_march.rs (the harness's rigid phase / release / subiterated coupling with its acceptance rule, no rescue machinery, death returned not panicked), tests/turek_hron_fsi2_overset.rs (RTX_FSI2O_* knobs); rtx-cfd: CurvilinearPisoSolver::wall_tractions (per-face pressure + full-stress traction, surface_force sums the same terms bit-identically); Interface::edges (bottom/tip/top for the generator); cylinder_flag_mms RTX_CF_BEND (P5-0 gate iv: Stokes orders 2.14 / 2.09 on the flag bent to 80 mm) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 07:16:53 -07:00
Omar SobhandClaude Fable 5.1	c2451fbacf	rtx-cfd: P5-0 — cylinder_flag_patch_deformed / cylinder_flag_outline_deformed: the O-grid around the cylinder and the FEA's deformed flag edges (FlagEdges bottom / tip / top), edges resampled at the rigid outline's graded arclength spacing, root fillets from the rigid construction, the tip semicircle from the deformed tip's centre and axis; the O-grid body factored out (o_grid_from_outline, hull_source) and the rigid generator kept bit-identical (its pins pass); gates: zero displacement reproduces the rigid outline to 6e-17 (mesh 2.5e-8 through the hull/Winslow pipeline, recorded), ±80 mm cantilever shapes valid at 80° with wall row 0.43 h, along-body 0.196 h, wall nodes on the edges to 6e-17, ny = 41 overlap builds ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 07:10:01 -07:00
Omar SobhandClaude Fable 5.1	cee9adef26	rtx-cfd: overset_cfd23 RTX_OVERSET_CFD23_PHASE=N — the momentum chain's stages sampled every N steps and averaged over the window; over whole shedding periods the unsteady terms vanish and the averaged chain is exact (the patch balance's unstored unsteady term included) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 04:14:55 -07:00
Omar SobhandClaude Fable 5.1	1a8f4aaebe	rtx-cfd: OversetPisoSolver::set_time; overset_cfd23 resumes a march from a saved field (RTX_OVERSET_CFD23_RESUME_T, _T_START) — CFD3 ny = 82's wake is still growing at t = 6–9 s (half-window amplitudes 187 / 339), the settled amplitude needs t = 15 ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-07 00:08:27 -07:00
Omar SobhandClaude Fable 5.1	ec17217e9e	rtx-cfd: overset_cfd23 RTX_OVERSET_CFD23_ND=explicit — the patch's across-diffusion explicit (dt limit then includes the n-spacing) for the 10 mm damping-floor probe; field tags carry it ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-06 20:44:07 -07:00
Omar SobhandClaude Fable 5.1	11d001fe48	rtx-cfd: solver_metric_force carries the scheme's limited face correction with the predictor's far-upwind choice, so the flux form is the solver's under TVD too (CFD2 ny = 41: three boxes spread 1.8 N/m → 5e-13; the upwind-only form read 120.2 for a solver box of 126.0) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-06 17:42:47 -07:00
Omar SobhandClaude Fable 5.1	ce3cbcce57	rtx-cfd: overset_cfd23 — Turek–Hron CFD2/CFD3 on the overset (the harness's ramped inflow from rest, TVD background and patch, 3-round cap), loads by the patch wall stress with the solver-flux-form box and the CV formula beside it as window statistics, CFD3 frequency from lift crossings, the solver-metric momentum chain at the final state (solved-face residual is the pin), save/load of the fields by case; momentum_residual checks the far-upwind neighbours explicitly under a limited background (the van Albada limiter swallows a NaN silently) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-06 17:10:18 -07:00
Omar SobhandClaude Fable 5.1	36af178980	rtx-cfd: overset_cfd1 RTX_OVERSET_ROWS — the overlap depth (patch rows kept non-hole below the acceptor row, default 4) as a knob for the §5.11 band probe; saved-field tags carry it; rows ≤ 3 are refused by the map at ny = 41 (acceptor donors reach the hole at the flag tip) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam	2026-09-06 15:30:31 -07:00
Omar SobhandClaude Fable 5.1	4c000266d9	rtx-cfd: overset momentum residual carries its pieces per ring face (time, convective, diffusive, pressure); overset_cfd1 offline probes on the saved fields — RTX_OVERSET_CFD1_FRONT dumps the cylinder-front faces by piece, RTX_OVERSET_CFD1_RAW re-evaluates the ring on the raw interpolated stamping without balance_fringe_fluxes (the balance is not the ring's source: +0.241 raw vs +0.247 balanced at ny = 41 upwind) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 14:37:08 -07:00
Omar SobhandClaude Fable 5.1	0215c7d6a5	rtx-cfd: CurvilinearPisoSolver::momentum_balance — the patch's own momentum balance on its solved cells in the scheme's fluxes (outward ρFu_f with the predictor's face value, Laplacian-form μ∇u·S on the solved/acceptor interface and the wall, the least-squares pressure volume sum vs the face-pressure integrals); flux_force, wall_force, pressure_defect δP; overset_cfd1 prints it and the acceptor band's mismatch, saves the patch flux, and RTX_OVERSET_CFD1_LOAD=dir runs the diagnostics offline on saved fields ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 14:13:04 -07:00
Omar SobhandClaude Fable 5.1	e31576d543	rtx-cfd: OversetPisoSolver::solver_metric_force — the box force in the predictor's own flux form (upwind convective, diffusive, cell pressure on the momentum control volumes' faces, minus the unsteady term); box-independent to rounding in the active region (five boxes spread 2e-12 at step 5 vs the CV formula's ±0.5 %); overset_cfd1 prints wall − box = ring Σr + rest and saves the settled fields under RTX_OVERSET_CFD1_SAVE ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 13:47:43 -07:00
Omar SobhandClaude Fable 5.1	6f9b0d43b2	rtx-cfd: OversetPisoSolver::momentum_residual — the background predictor's own staggered stencil (u_rhs/v_rhs, factored out of the predictor bit-identically) evaluated on every face of a NaN-masked field; solved faces read rounding, the active–fringe interface reads the composite's pressure level offset δ·h (cancels in the sum), prescribed fringe–fringe / fringe–hole faces read the stamping's momentum injection; hole ghosts (p, u, v) from a band widened three rows into the hole make every ring face evaluable; overset_cfd1 prints the buckets, the ring x-bands and δ at the settled state; pin: residual vanishes on the solved faces ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 13:25:14 -07:00
Omar SobhandClaude Fable 5.1	cbec40b999	rtx-cfd: overset_cfd1 prints five CV boxes (all outside the fringe ring), the wall pressure/viscous split and the fringe extents at the settled state ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 10:14:43 -07:00
Omar SobhandClaude Fable 5.1	134ac03870	rtx-cfd: OverlapMap::region_force — momentum flux into a background region (control-volume face formula, one-sided next to holes); overset_cfd1 prints the four momentum routes (CV box, ring outer, hole boundary, wall) and their defects at the settled state ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 09:08:01 -07:00
Omar SobhandClaude Fable 5.1	5f780447de	rtx-cfd: PatchConvection::TvdVanAlbada — van Albada deferred correction on the curvilinear predictor (downwind-side linear weight, gradient-ratio r over the face d lengths, far-upwind across the opposite face, boundary faces upwind); annulus MMS orders 2.10/1.69 at 0.24× upwind; cylinder-flag MMS orders 1.98/1.97 (1.06× upwind — diffusion-dominated, recorded); knobs RTX_OVERSET_CFD1_TVD, RTX_OVERSET_MAX_ROUNDS, RTX_CF_SCHEME ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-06 00:21:48 -07:00
Omar SobhandClaude Fable 5.1	02c855b9c4	rtx-cfd: overset Schwarz stall rule guarded (fires only within 10× the tolerance) — unguarded it cut CFD1's transient at round 3 every step and the coupled march diverged at ny=62 (pressure 4e4 → 1e140 by step 450); CFD1 harness knobs (stall, step cap, trace) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 21:01:57 -07:00
Omar SobhandClaude Fable 5.1	00f73eb70a	rtx-cfd: overset CFD1 harness — the steady-march stall rule (stall_rounds 2) actually enabled (the previous commit's edit had missed its anchor) ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 20:28:25 -07:00
Omar SobhandClaude Fable 5.1	9761cf2319	rtx-cfd: overset P4 — CFD1 on the composite (tests/overset_cfd1.rs): ny=41 wall drag 15.2156 (+6.46%), lift 1.0879 (−2.78%), CV drag 15.528 (+8.64%), routes 2.0% apart (staircase +10%); 28550 steps, 2099 s at dt 4.57e-4 with 5.0 Schwarz rounds mean (stall rule off) — steady-march stall rule on for the next rungs ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 20:27:52 -07:00
Omar SobhandClaude Fable 5.1	45ff34da8f	rtx-cfd: overset P4-0 — the O-grid around the Turek–Hron rigid body (cylinder + flag), gated ... patch_gen::{cylinder_flag_outline, cylinder_flag_patch, winslow_smooth, respace_rays} (+ convex_hull, offset_convex_polygon, nearest_on_polyline): the outline CCW then reversed to clockwise (tip semicircle 16 cells, junction fillets of a FIXED radius with 3 cells, straights graded 0.3 h → h, cylinder arc at h); the outer ring the 6 h normal offset of the body's convex hull; initial pairing by the inner point's normal offset projected onto the hull offset (an arclength-proportional pairing folded the transfinite grid at the tip: rays crossed where the curvatures differ); Winslow (TTM) smoothing of the interior with the outer nodes SLIDING along the hull offset (each re-placed at the nearest point to the extrapolated ray), then re-spacing along the smoothed rays to the across stretch. Gates (tests/patch_cylinder_flag.rs): ny = 41/62/82 → 143×12 / 183×12 / 225×12 cells, positive, wall row 0.23 h (fillet max 0.37 / 0.43 / 0.50 h), worst non-orthogonality 76.6 / 69.1 / 63.3° at the concave fillets (structural: a concave arc's normals converge at its centre), classification of the benchmark background with both donor invariants. P0 MMS on these meshes (tests/cylinder_flag_mms.rs, exact acceptors, line-implicit): Stokes orders 2.17 / 2.13, upwind 2.00 / 1.86 (cell Péclet ≈ 0.1), divergence ≤ 9e-14 — the fillet skew costs nothing measurable. Rule: a refinement ladder's geometry must be fixed in physical units — with fillet = h/2 the Stokes orders read 1.74 → 1.31, the O(h) boundary perturbation masquerading as a scheme defect; the fillet is a parameter (5 mm across the ladder). Also: the P3b knock-outs H1/H2 on the balanced default (no effect), the P3 §5.10 record in the falsifier's header. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 19:50:14 -07:00
Omar SobhandClaude Fable 5.1	62df6bd628	rtx-cfd: overset P3b — the reclassification impulse located (the fringe ring is a staircase of the interpolated velocities' mass defect) and removed by a converged fringe flux balance (default on): falsifier max spike 594 → 5.50 N/m at the FSI2 step (staircase 6490), 10.95 / 16.79 at dt/2 / dt/4 (12600 / 25600), rms spike 0.07% of the force, far probe 6 (7900), KE per event 4.9e-3 J/m falling with Δt (2.6 fixed) ... OverlapMap::balance_fringe_fluxes: Gauss–Seidel through the prescribed faces of every fringe cell to 1e-12 of the prescribed flux scale (≤ 50 sweeps), after every fringe stamping (3 fixed sweeps 101 N/m, 10 sweeps 5.5 — converged is the rule). OversetParameters: fringe_flux_balance (default on, RTX_OVERSET_NO_BALANCE off), fringe_balance_tolerance, refill_turned_active (measured no effect: 593.7 → 593.8; kept as the record), stall_rounds opt-in. P3b locating trace RTX_OVERSET_TRACE_SP (continuity source by class change in cell volumes/step, stored-pressure jump of turned-active cells): the flipped cells' mass source ≤ 6e-3 cell volumes/step, their stored pressure 5–10% of the range off their neighbours (4.4% on the static MMS — the meshes' discretization disagreement). Knock-outs refuted (RTX_OVERSET_H1 keep own face velocities, H4 no warm start, pressure refill): 593–597 N/m each. S4 MMS with the balance: velocity errors within 0.1% of the pinned values, the background's overlap mass defect 1e-13 by construction, pressure errors unchanged. overset_mms prints pressure diagnostics; overset_falsifier records the balanced ladder (regression guard 20 N/m at dt; RTX_OVERSET_FALSIFIER_STRICT asserts the registered gates — (ii) holds at dt, misses at dt/2, dt/4; (iv) fails: residual ∝ 1/Δt^0.8). Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 19:16:16 -07:00
Omar SobhandClaude Fable 5.1	6b8837301f	rtx-cfd: overset Schwarz stall detection is opt-in (stall_rounds, default 0): right for a steady march (n=64: 2.26 rounds mean, no cap hits, L2 identical), wrong for a transient (falsifier max spike 594 → 4044 N/m when on); the MMS harness sets 2 ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 18:35:06 -07:00
Omar SobhandClaude Fable 5.1	e2edff9b1d	rtx-cfd: overset A-P3 — the falsifier plate on the overset (FAILS the registered gates by one order less than the staircase); wall force; composite pressure-level pin; Schwarz stall detection ... patch_gen::{stadium, graded_fractions}: the falsifier plate as a stadium O-grid (semicircular ends r = half-thickness; 16 cells per end arc, straights graded 0.30 h -> h at 1.15, offset 6 h, 12 rows stretched 4x; 148x12 cells, every ray a normal, worst non-orthogonality 4 deg). CurvilinearPisoSolver::surface_force (+ PatchLoad): F = sum(-p_f S_f + mu (grad u + grad u^T)_f . S_f) on the wall faces with the wall cell's LSQ gradients (wall Dirichlet in the velocity fit); HELD on the phantom circle against the exact stress integral: 1.3e-2 / 6.3e-3 / 3.6e-3 at n = 32/64/128 (orders 1.05 / 0.81), 22x the staircase's accuracy. OversetPisoSolver: the composite p' level pinned to zero mean over the active cells every round (the coupled problem is pure Neumann; the temporal warm start handed each step's level to the next — background pressure 1e7 growing 5e4 per step on the falsifier; an unpinned level also inflated the relative Schwarz stop); stall detection (no progress over three rounds = the inner solvers' noise floor; 6560 of 150k steps burned the 20-round cap at n = 64, a 7.5 h n = 128 march); schwarz_stalled in the result. tests/overset_falsifier.rs (records; RTX_OVERSET_FALSIFIER_STRICT asserts the registered gates, _LADDER runs dt/2 and dt/4, _TRACE the top-12 spike steps): max spike 594 / 981 / 1720 N/m at dt / dt/2 / dt/4 (staircase 6490 / 12600 / 25600), rms spike 61-89 (810), far probe 502-1509 (7900), KE injection 0.16-0.21 J/m per event on the common cell set (2.6) — every large spike a ~104-cell full-row reclassification; exponent -0.77 (-1.0). The registered 5% gate (8.75 N/m) is missed 68x: the overset's own reclassification impulse is the finding (omni-cortex overset_metal_campaign.md §5.10); P3b = locate per cell, then the fringe flux balance. tests/patch_stadium.rs, curvilinear_loads.rs, overset_common::plate_patch. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-05 04:32:43 -07:00
Omar SobhandClaude Fable 5.1	afd1bff6ee	rtx-cfd: overset A-P2 — the patch overlaps the background (OversetPisoSolver), gated S1–S5 ... Background = the embedded solver with a mask from the overlap classification (embedded/{mod,projection}.rs: module split, projection's solve/apply halves, set_overlap, fringe p' Dirichlet by elimination into extra_diag/rhs, anchor dropped, set_inner_stop_factor, phase API begin_step/solve_correction/ apply_correction/end_step; advance rebuilt on the phases — every suite digit- identical, FSI2 default line-for-line). Patch = the curvilinear solver with an acceptor ring (set_side_velocity; set_acceptor_ring/stamp_acceptors/ set_acceptor_correction; acceptor Dirichlet by elimination into PressureSystem.links so the BiCGSTAB stop stays in flux units — identity rows measured unconverged at 2431 iterations; same phase API). overset/overlap.rs: OverlapMap — hole/fringe/active from the patch's own indices (hole = body or k <= nn-1-overlap_rows, DEFAULT_OVERLAP_ROWS = 4 from the 2.9 h depth budget), dual-quad inverse-bilinear donors patch→fringe, lattice donors →acceptors, both invariants asserted, mass-defect measures. overset/mod.rs: OversetPisoSolver — advance (exchange rebuilt BEFORE the predictors from the previous corrected field), alternating Schwarz on the acceptor p' vector with Anderson(3) (plain Schwarz measured 0.82/round: floating patch, Neumann wall) and the previous step's vector as warm start (1 round/corrector at steady state), stop relative to the STEP's p' scale (the MG absolute stop is 1e-9/dt² in pressure — the whole second correction), set_patch_mesh, snapshot/restore carrying the warm-start vector. Gates: overlap linear-exact 1e-13, quadratic orders 1.96/1.99 (acceptors), 1.40/1.91 (fringe); half-couplings: patch with exact acceptors Stokes 2.07/1.98 + 2.08/1.98, upwind 0.84/0.84, background with exact fringe 7.86e-3/2.90e-3/ 1.09e-3 (1.44/1.41); two-mesh MMS n=32/64: background 8.717e-3/4.207e-3 (1.03x/ 0.97x the embedded circle), patch 1.322e-2/6.904e-3 (1.5-1.6x), orders 1.05/ 0.94, patch div <= 5e-13, overlap mass defect 3.6e-3 -> 8.2e-4 of the overlap flux (under the registered 1e-3 from n=64; disclosed at 32); motion: stationary patch through set_patch_mesh bit-identical, snapshot/restore with a pending mesh bit-identical, translating phantom circle 1.22x/1.19x the static level over 4.5 cells. Inherited, disclosed: poisson_equivalence's no-body multigrid pin fails by 3.9e-9 at d46fb0b (M1's commit; verified in a clean worktree). Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-04 19:24:13 -07:00
Omar SobhandClaude Fable 5.1	d46fb0b7a7	rtx-cfd: overset A-P1 GATED — the curvilinear patch moves and deforms under an exact 2-D DGCL ... StepGeometry (motion.rs): time-averaged face vectors S̄_f = ½(S^n + S^{n+1}) and swept volumes δV_f = S̄_f·δc_f — exact for linear node motion on any quad, so Σ sign δV_f = V^{n+1} − V^n is algebra (1.8e-14 measured; the EndOfStep control 2.1e-3). CurvilinearPisoSolver::set_mesh(next) names the end-of-step geometry; advance swaps it in, rebuilds operators + pressure matrix on it (L_f, LSQ gradients, no mesh-velocity term in the projection), keeps the old mesh for V^n and the explicit boundary data; predictor in the conservative ALE form V^{n+1} û = V^n u^n + dt(−Σ sign (F − δV/dt) u_f + ν D + f V^n), written as u·(V^n/V^{n+1}) + … so a stationary mesh is bitwise the static path; fluxes on S̄_f; snapshot carries both meshes; swept_face_rule knob (Trapezoidal default, EndOfStep = negative control). Stokes limit keeps the mesh flux (was dropped with convection) and centres it (upwinding it cost an order: 1.06/1.00). Gates (tests/curvilinear_ale.rs, 11 tests, 83 s): uniform flow on a wiggling AND bending annulus 4.44e-15 over 400 steps, p exactly 0, 0 pressure iterations; control deviates 4.9e-5; stationary mesh through the moving path bit-identical (both diffusion variants); snapshot/restore on the moving mesh bit-identical; Taylor–Green orders unchanged — upwind 0.995/0.976 vs fixed 0.987/0.975 at 1.05× error, Stokes 1.92/1.97 vs 1.94/1.99 at 2.4×, moving annulus 2.11/2.02; linear-field falsifier 1.95/1.92 (annulus), 1.91/1.43 (square, sliding wall nodes). P0 ladders re-run identical to every digit. Rule from the diagnosis: start a moving run ON the t = 0 mesh and sweep less than a cell per step — a first step that jumped 2–4 cells imprinted an O(displacement) error no refinement removed (dt- and motion-independent). Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-04 17:00:04 -07:00
Omar SobhandClaude Fable 5.1	c63d79c300	rtx-cfd/rtx-fsi: overset A-P0 GATED + M1 precision probe — curvilinear collocated PISO: relative-reduction pressure stop (the absolute stop floored |du/dt| at 2e-4 on 64²), line-implicit-n sign fix, adjustPhi; gates: Cartesian reduction 1.37–1.40x the staggered error at orders 0.83/0.90; skewed stretched periodic annulus Stokes orders 2.30/2.06 (explicit and line-implicit), upwind 1.08/0.80; Poiseuille exact to 1e-9 on Cartesian and affine-sheared periodic channels (both diffusion variants), varying-skew channel order 2.02 (v 1.9), cell mass 1e-14; divergence ≤ 1e-11 relative every step; snapshot/restore bit-identical. M1: poisson.rs multigrid hierarchy generic over MgScalar (f32/f64), f64 CG keeps its own fine level; MgPrecision on MultigridParameters/EmbeddedParameters/PisoParameters, set_poisson_precision, harness RTX_FSI2_POISSON_F32 (march + noise probe, printed marker); f64 arm bit-identical in vivo (FSI2 default line-for-line with 08-31), f32 arm holds the noise floor and stall pins and the FSI2 band; poisson_equivalence f32 arm ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-04 12:40:43 -07:00
Omar SobhandClaude Fable 5.1	52da75a3a9	rtx-cfd: curvilinear collocated PISO on a structured patch (overset A-P0, WIP) — PatchMesh (right-handed s,n; periodic seam with shift; face metrics), patch generators (TFI, skewed annulus, sheared/varying-skew channels), CSR + Jacobi-BiCGSTAB, the Zang–Street–Koseff incremental step with the node-based 9-point L_f, LSQ gradients, explicit and line-implicit-n predictors, adjustPhi; tests: mesh metrics (5 green), operators exact on linear fields incl. the seam (green), sparse (2 green), MMS ladder (Cartesian 16/32: 1.37–1.39x the staggered error, order 0.83; n=64 stalls at a |du/dt| floor 2e-4 — open, tolerance-scaling hypothesis), annulus/Poiseuille not yet run ... Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-04 05:00:08 -07:00
Omar SobhandClaude Fable 5.1	1347bc6772	test(rtx-cfd): fresh-cell falsifier — circle body, far-field probe, kinetic energy per step, speed knob, and the per-flip kinetic-energy split by face class (interior / fresh / dead) ... The split locates the flip's velocity change: 71% (plate) / 61% (circle) on the DEAD faces — fluid faces the wall reaches, overwritten with the wall-side reconstruction in one step (a ~0.25 U_b jump per face) — 27–38% in the interior response, ~1% on fresh faces. Five treatments leave the per-flip impulse/energy unchanged on this falsifier (all measured, none kept unless already committed): substeps, the swept-volume source (40x worse), the fresh-face field extension, face apertures + wall-relative divergence in the projection (-12%, and it breaks the static invariants), and imposing the t^{n+1} wall before the predictor. The impulse is intrinsic to a binary staircase wall that stands still between flips and jumps a cell; the record is in omni-cortex docs/fresh_cell_gcl_campaign.md. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-03 11:56:04 -07:00
Omar SobhandClaude Fable 5.1	c9492d3e1e	test(rtx-cfd): fresh-cell falsifier extended (circle body, far-field probe, kinetic energy, speed knob) + print-only divergence trace; two candidate fixes REFUTED on it (swept-volume source 40x worse at either sign; fresh-face field extension no effect), both kept default-off with their verdicts ... Phase 1 of omni-cortex docs/fresh_cell_gcl_campaign.md. The mechanism of the moving-body force spikes is measured from four directions: per-flip force amplitude ∝ 1/dt, kinetic energy injected per flipped cell 0.048 J/m independent of dt and body shape (plate row vs circle), felt at a far-field pressure probe, and ∝ U^2 (2.60 / 0.64 / 0.15 J/m at U = 1 / 0.5 / 0.25). A binary mask's wall position jumps by one cell at every flip and the fluid answers with a fixed impulse. Neither the swept-volume source (the wall faces already carry the swept volume — the source double-counts it) nor the fresh-face velocity is where it lives. Next: the virtual cut cell in the projection (apertures + the wall-relative divergence), registered in the campaign doc. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-03 11:40:28 -07:00
Omar SobhandClaude Fable 5.1	23eb996a9f	test(rtx-cfd): the fresh-cell falsifier — an oscillating flag-sized plate on the FSI2 grid and dt; force spikes track fresh cells (90% at dt) and their per-event amplitude scales as dt^-1.0 (rms dt^-0.44) ... Phase 0 of omni-cortex docs/fresh_cell_gcl_campaign.md (Seo & Mittal's oscillating-body test on this embedded solver). Plate 0.35 x 0.02 m, 1 m/s peak, 80 mm amplitude, still fluid, h = 1/152, dt = 3.24e-4 and its halvings; force sampled as the coupling samples it. Measured: at rest exactly zero; moving, 648 fresh cells per sweep at every dt, rms spike 810 / 1080 / 1490 N/m and MAX spike 6.5e3 / 1.26e4 / 2.56e4 at dt, dt/2, dt/4 — the per-event impulse doubles with each halving (a fixed whole-cell volume error per fresh cell delivered in one step, the raw (dV/dt)|1 - CFL_b| source), against a physical added-mass force of ~1.3e3. RTX_FRESHCELL_LADDER=1 runs the ladder, RTX_FRESHCELL_CSV=<dir> dumps per-step records. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-03 11:24:24 -07:00
Omar SobhandClaude Fable 5	4aec4e589d	rtx-cfd/rtx-fsi: the FlowField->clawview exporter — real FSI fields through the viewer, end to end ... The march gains RTX_FSI{2,3}_FFLD (MarchConfig::ffld_dir, off by default): every snap_every committed steps (10 when SNAPEVERY is 0), dump the committed FlowField (FlowField::save, bit-exact), the solver's own fluid-cell mask and the interface polygon as text sidecars, plus an index.csv. Reporting-only after acceptance; the FSI2 default with the knob off reproduces every printed digit of the warm-start baseline (uy 3.4921 +- 3.5109, conservation 8.25e-12). The exporter (rtx-cfd examples/ffld_to_vtk): a dump directory -> clawview-readable legacy VTK — per-snapshot 2D triangle meshes (one selectable point scalar --field p|umag|vort, the 0/1 fluid mask as integer CELL_DATA) and an optional space-time volume (--spacetime: frames stacked along z = time, prisms split to tets, POINT_DATA phi), which clawview's slice-plane animation plays as a transient movie. Verified end to end with REAL fields, not synthetic: a 29-frame FSI3 release-transient dump (t 4.0 -> 4.1, 64 MB) exported to 29 snapshots + a 984,312-tet space-time volume; the clawview server loaded both (176,320 nodes volume; 23,877-node snapshots) and served live cross-sections (time slices), vorticity isosurfaces and contours from them. The check caught two real viewer-contract constraints now encoded in the exporter: clawview's legacy-VTK path parses CELL_DATA scalars as INTEGER markers only, and supports exactly ONE point scalar (all POINT_DATA blocks append into `phi`) — multi-field snapshots need the .clwv route, out of scope here. Closes the top open thread of the fifteenth-session handoff (the FSNP/FlowField->viewer exporter); the mesh-repo push and the claw-gds cargo feature remain clawview-side items. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-30 14:45:54 -05:00
Omar SobhandClaude Fable 5	4d2cede7bc	rtx-cfd: warm-start the first corrector's pressure-correction solve — measured 2.5x fewer PCG iterations where it counts ... The MG smoother (neighbour_sum + PCG, 34-40% of the fluid) was the remaining fluid cost. Measured in vivo (FSI2 default, temporary iteration counters): 2.7-3.0 PCG iterations/solve from a zero initial guess. The correction field is temporally correlated step to step, so project() now seeds the FIRST corrector's solve from the previous step's p' (current fluid cells only — the p'=0 invariant on non-fluid cells survives the copy-back); later correctors and the SOR fallback start from zero exactly as before. The corrector restriction is measured, not guessed: the all-correctors draft cut the rigid phase 2.8 -> 1.27 iters/solve but cost 3.9/solve in the coupled phase (baseline 2.56) — corrector 2 solves for a much smaller correction and corrector 1's full-magnitude p' is a WORSE guess than zero there. First-corrector-only: rigid 2.8 -> ~1.1 (best of the three variants), coupled 2.62 ~= baseline. Total PCG iterations on the FSI2 default: 55,088 -> 32,836 (1.68x fewer). Wall: FSI2 default 225 -> 172 s, FSI3 default 343 -> 249 s. Session cumulative (banded LU + indexed SDF + warm start): FSI2 524 -> 172 s (3.0x), FSI3 944 -> 249 s (3.8x). This is a TOLERANCE-LEVEL solver-path change (each projection reaches the same true-residual stop from a different start), and the FSI3 release-window pins fired for the third and fourth time across the drafts — completing the picture: EVERY windowed observable of the [4.0, 4.2] release transient is branch-sensitive (four measured branches now recorded in the test: uy mid 10.77/6.02/2.91/8.88, amp 23.6/25.2/24.6/19.9, ux mid -2.90/-2.91/-2.56/-1.82, retries 2/0/1/1). The release bands are re-pinned as gross-physics tripwires around the measured scatter; the load-bearing regression pins for solver changes are the settled-cycle study bands, whose re-verification under this change is launched (verdicts to solver_status.md). Protocol: FSI2 default green (uy 3.4921 in-band), FSI3 default green under the re-pinned release bands (deterministic across two runs), FSI1 green, noise-probe floors identical, rtx-cfd suite + rtx-fsi quick tests green. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-30 08:54:27 -05:00
Omar SobhandClaude Fable 5	6c48e53998	rtx-cfd: indexed polygon SDF — bit-identical queries, the fluid's measured hot function cut ... The 2026-08-30 fluid profile (symbolized samples, rigid AND coupled phases of the FSI3 default) attributed the fluid step to the function: polygon_signed_distance 51% rigid / 35% coupled — the embedded mask rebuild and its ghost reconstruction walk every edge of the ~150-vertex interface polygon for every cell-centre and face query, every step. (Also measured, refuting the parked consolidation: Level::new — the MG hierarchy build — is 0.5-0.7% in BOTH phases; caching it would buy nothing. The MG smoother at 34-40% is the honest remaining fluid cost.) PolygonSdf (solvers/incompressible/polygon_sdf.rs): a binned edge index whose query is BIT-IDENTICAL to polygon_signed_distance by construction — per-edge distances use the same float ops, the ring search provably visits a superset of the argmin (convex-projection lower bound sqrt(d_out^2 + ((r-1)b)^2)), and parity XORs the same ray tests over exactly the straddling edges (y-binned). Equality is ASSERTED, not assumed: tests compare to_bits against the brute force over ~40k adversarial points (flag-like walks, random polygons with degenerate zero-length edges, horizontal-edge/vertex-y rays). Wired into EmbeddedBody::polygon and the FSI harness's shared geometry (rebuilt per set_geometry, ~microseconds for 150 edges). Verification — the bar for a bit-exact change is digit identity, and it holds: FSI2 and FSI3 committed defaults reproduce EVERY printed digit of the banded-LU baseline logs (uy 3.7732±3.7920 / 6.0229± 25.2190 mm, conservation 8.26e-12 / 1.49e-12, rigid drags 121.4 / 426.9); rtx-cfd full suite 0 failures; rtx-fsi lib/piston/transfer/ FSI1 green. The study pins need no re-run: the trajectories are unchanged by construction and confirmed by measurement. Wall clock: FSI2 rigid 323 -> 167 s (1.93x), whole default 400 -> 225 s; FSI3 rigid 420 -> 250 s (1.68x), whole default 539 -> 343 s. Cumulative with the banded LU this session: FSI3 default 944 -> 343 s (2.75x), FSI2 524 -> 225 s (2.33x). Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-30 07:47:42 -05:00
Omar SobhandClaude Fable 5	9fe9d7f74a	rtx-cfd + rtx-fsi: ECSW campaign phase 1 — snapshot dump + FlowField save/load ... FlowField::save/load serialize the complete field state bit-exact (all twelve matrices including *_old, predictors and sources, so a load is a true restart state), with a roundtrip test asserting to_bits equality on every value and rejection of truncated/corrupt files. The march gains an ECSW snapshot knob (RTX_FSI{2,3}_SNAP path, SNAPEVERY, default off): every N committed steps it appends an FSNP record — t, full-DOF displacement/velocity/acceleration (what rtx_fea::mor's pod_basis/train_ecsw consume, plus what the phase-4 dynamic reduction will need) and the committed sparse nodal load for the offline full-vs-reduced replay. Reporting-only: reads committed state after acceptance, no float ops on the solver path. Verified: smoke run's FSNP parsed by an independent reader (570 DOFs, correct record count, physical values); FSI2 committed default digit-identical with the knob off. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-28 21:56:37 -05:00
Omar SobhandClaude Fable 5	bff84ccdcc	rtx-cfd: mask hysteresis — sticky cell classification against a reference mask ... The measured FSI3 killer is the bistable mask: one geometry (|d| identical to 4 digits) samples two load branches (60 vs 120 kN), and the traced s=1 death is the secant walking a 20x load cliff (68,886 -> 1,307,938 N over a 1e-3 candidate change). A sticky band makes the load map single-valued at the crossing: formerly-fluid cells flip only at phi < -band, formerly-solid at phi > band, classified against the mask held at rebuild time — in a coupling loop, the restored committed step-start mask. Band 0 is structurally bit-identical (phi > -0.0 <=> phi > 0.0) and verified digit-for-digit on both committed defaults (FSI2 and FSI3, every physics digit). Measured cost on the translating-circle MMS at band 0.25h: +0.5% field error (u/p ratios 1.17/2.12 vs the no-hysteresis moving levels 1.16/2.11); flip delay = band/(v dt), deterministic. Exposed as RTX_FSI{2,3}_HYST in multiples of h_min. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-26 15:27:09 -05:00
Omar SobhandClaude Fable 5	4534d90684	rtx-fea + rtx-cfd: the single-step seams FSI2 stands on ... rtx-fea: NonlinearDynamicAnalysis refactored onto a NonlinearDynamicStepper - set_nodal_forces on both (the interface load of a coupling subiteration, replaceable between steps and between subiterations of one step); - step(&DynamicState) is a pure function of the start-of-step state and the current forces - commits nothing, so a partitioned coupling re-runs one Newmark step to the interface fixed point (the piston semantics); - run() marches through the same stepper: one code path, pinned from both ends (linear limit, CSM3, and a new manual-drive == run() assertion); - new test: a nodal step load oscillates about the *static* nonlinear analysis's deflection (cross-code-path, mean within 3%, amplitude 6%), with re-run determinism and force-swap sensitivity asserted mid-march (a one-step response to a force change is ~ beta dt^2 - the first assertion draft demanded 10% and was corrected against the physics). rtx-cfd: the subiteration seam and the moving no-slip closure - EmbeddedPisoSolver::snapshot()/restore() (mask + time + init flag; the mask is now Clone): re-running a fluid step within a subiteration is bit-identical to never having diverted - proven on a moving body with cells flipping in the re-run window; - polygon_interface_velocity: nearest-edge linear interpolation of per-vertex velocities, exact for the linear-along-edge boundary data a finite-element interface hands over - the no-slip closure that replaces FSI1's zero-velocity polygon. Suites: rtx-fea 567, rtx-cfd 325, rtx-fsi piston+transfer - all green. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-20 20:00:49 -07:00
Omar SobhandClaude Fable 5	c0f5a86f03	rtx-cfd: the embedded-body pieces FSI1 stands on (belongs with b82f307) ... EmbeddedMask::traction_at (the per-sample traction factored out of surface_force, so a coupling loop can load a structure at its own quadrature points), EmbeddedBody::polygon and the public polygon_signed_distance (a deformable interface as a vertex list, usable behind a lock through EmbeddedBody::from_sdf). Left unstaged by mistake in b82f307 — that commit's FSI1 test needs these to compile. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 17:22:44 -07:00
Omar SobhandClaude Fable 5	0ad31abb6b	rtx-cfd: F2 — the moving embedded body, and falsifier 3 measured ... EmbeddedPisoSolver::set_moving_body: the mask is rebuilt at the end-of-step geometry every step, and the new mask's ghost values are reconstructed FROM THE PREVIOUS CORRECTED FIELD (EmbeddedMask:: impose_from — the boundary-history principle extended to a moving wall), so a stationary body run through the moving path is bit-identical to the static path, which is the first test. A velocity face that flips solid -> fluid enters the new interval holding exactly the ghost reconstruction the previous step left on it — a consistent near-wall value, not garbage; a fresh pressure cell is refilled from its fluid neighbours before the predictor's gradient can read the value it kept while inside the body. The body must move under a cell per step (the convective dt limit already enforces this for bodies slower than the local peak velocity). EmbeddedResult reports fresh_cells. tests/embedded_moving.rs: - a stationary body through the moving path: 0.0 difference over 100 steps (and zero fresh cells, identical ghost corrections); - a circle (r = 0.2) translating through the steady manufactured field with the exact field as its surface velocity — the solution must hold still while the mask sweeps 84 cells fresh over 300 steps at n = 32: max L2 velocity error 9.85e-3 = 1.16x the static steady level (8.489e-3), max L2 pressure error 4.67e-2 = 2.11x the static level (2.22e-2), bulk |div u| 1.6e-7, projection residual 5.9e-9 every step. That pressure ratio is the geometry decision's falsifier 3 (omni-cortex docs/turek_hron_geometry_decision.md): fresh-cell transients sit at ~2x the static discretisation error, not orders above it — the falsifier does not fire and no cut cells are needed. Measurement note, recorded in the test: the divergence of body-adjacent cells read after the end-of-step ghost re-imposition is a one-step lag by design (the next projection honours the re-imposed prescribed fluxes — the same lag the static path has); the continuity claims are the projection residual and the bulk divergence over all-fluid-faced cells. Deferred: an oscillating-cylinder benchmark against published force histories (Duetsch et al. 1998) when the FSI rungs need it. rtx-cfd 321 -> 323 green. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 13:07:28 -07:00