65 Commits

Include renames

Author	SHA1	Message	Date
Omar SobhandClaude Fable 5	045e145962	test(rtx-fsi): RTX_FSI{2,3}_ES stiffness override for the TWIN-2 parameter sweep ... The second knob of the TWIN-2 campaign (omni-cortex docs/twin2_stiffness_campaign.md): case_from_env now also reads RTX_{prefix}_ES over the case's benchmark Young's modulus, mirroring UMEAN exactly — digit-identical with the knob unset (verified in vivo on BOTH committed defaults against same-day baselines: FSI2 and FSI3 physics lines diff-clean, only compile/wall timings moved), a loud override line naming the benchmark value and E/E0 when set. The benchmark-inflow physics-band guard in both turek_hron tests widens to a benchmark-CASE guard (u_mean AND e_s bit-identical) so no measured band ever asserts off-benchmark; machinery invariants stay asserted at every inflow and stiffness. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-09-01 20:50:58 -07:00
Omar SobhandClaude Fable 5	c08abbdc4f	test(rtx-fsi): RTX_FSI{2,3}_UMEAN inflow override for the TWIN-1 parameter sweep ... case_from_env applies the knob over the case's benchmark inflow; unset, the same f64 flows and both committed defaults are verified digit-identical in vivo (physics lines diff-clean vs same-day baselines; only wall-split timing percentages moved). Physics bands in both tests are guarded to benchmark inflow — an off-benchmark march (the sweep) asserts machinery invariants only; its bands live in the TWIN-1 composition harness (omni-cortex docs/twin_composition_campaign.md). The override prints loudly so sweep logs are self-describing. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-31 21:25:30 -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	0b4f306ed1	rtx-fea: reduced Newmark (mor::dynamic) + the phase-4a offline replay — the ≥10x gate is REFUTED by measurement at the validated resolution ... The dynamic layer over ReducedNonlinearModel: reduced consistent mass V'MV (full element sum, never ECSW-sampled — ECSW weights are trained on internal-force virtual work and would conserve the wrong inertia), reduced_force_and_jacobian exposed (solve() refactored onto it), and ReducedNewmark mirroring NonlinearDynamicStepper::newmark_newton in reduced coordinates (same predictor, residual, tangent shape; no rescue ladder by design — a reduced Newton death is a finding). TDD (tests/reduced_newmark.rs): identity-basis march reproduces the full stepper to 2.4e-14 over 15 steps (both Newton loops tightened to 1e-10 so only solver rounding separates them); rigid-translation reduced mass = rho*A to 1e-9; a 6-mode POD basis tracks its training trajectory at 4.2e-4 rms against a 1.0e-4 projection floor. Phase 4a (fsi3_ecsw_offline.rs, fsi3_reduced_newmark_replay, env-gated): reduced Newmark replay of the harvested FSI3 trajectory at record cadence (dt_rec = 5x march dt), driven by the recorded end-of-step loads. Measured, m=12/20: - COST (dt-independent, the verdict): 3,068/3,580 us/step at 4.6/5.0 Newton iters — 2.0-2.3x the banded full-order structural step (7,200 us/pass, bandedlu_fsi3_ny62_t85). The >=10x gate needs <=720 us/step; one reduced eval alone costs ~640 us because phase 2 refuted hyperreduction (every eval loops all 70 elements). The gate arithmetic is closed: reduced Newton needs >=2 evals, capping the ROM at ~5x. THE CAMPAIGN GATE (pinned cycle bands at >=10x structural speedup) CANNOT BE MET at the validated resolution. - TRACKING at record cadence diverges in the release transient (dies t=4.35-4.45) — and the RTX_REPLAY_IDENTITY control dies EARLIER (t=4.13) in the exact subspace: the death is the 5x-coarse integration + aliased loads, NOT the reduction. The record-cadence replay cannot judge subspace dynamics; the projection floor (1.1e-3 at m=12) remains the honest subspace statement. Campaign verdict to be recorded in omni-cortex in the pre-registered words. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-30 07:07:49 -05:00
Omar SobhandClaude Fable 5	10c779e96e	rtx-fea: banded LU replaces the dense factorization on the Newton tangent — the march's cost center, fixed ... The 2026-08-29 profile attributed 98% of the structural step (79% of a coupled FSI pass) to LuDirect::factorize — nalgebra's dense full-pivot LU on the 560-DOF tangent, every Newton iteration. The tangent is banded (half-bandwidth ~26: the flag mesh numbers the short direction innermost). BandedLu (solvers/banded.rs): LAPACK dgbtrf-style column-major band storage, partial pivoting with kl fill rows, band limits measured from the CSR pattern per factorize, O(n·kl·(kl+ku)). Swapped into NonlinearDynamicStepper (tangent + rest-state mass solve); LuDirect untouched elsewhere. TDD: 10 manufactured-system tests green first run (recovery to 1e-12 vs exact and vs LuDirect across band shapes incl. full-bandwidth degeneration; zero-diagonal pivoting; indefinite shifted-stiffness tangent; singularity; per-solve refactorization). Solver-path change — full verification protocol run: - rtx-fea 29 binaries 0 failures; rtx-fsi lib/piston/transfer green. - FSI2 committed default: every printed digit IDENTICAL to the 2026-08-28 baseline (uy 3.7732±3.7920 mm, f 2.547, conservation 8.26e-12). FSI1 identical. Noise-probe floors reproduced. - Wall clock: FSI2 coupled phase 233 s -> 77 s (3.0x, 0.60 -> 0.20 s/step); FSI3 coupled 517 s -> 119 s (4.3x). Structure is no longer the cost center; the fluid's MG-caching consolidation is next. Finding 1: newton_rescue's vacuousness guard fired — the 2026-08-24 killer (symmetric 1e4 N mid-swing reversal) converges on the PLAIN path under partial-pivot rounding at every probed combo to 1e5 N. Re-provoked: asymmetric 1e4 -> +1e5 N reversal defeats plain Newton at swing steps 3, 4 AND 5 (not knife-edge); pinned at steps 4, whose coarse-vs-fine gap (0.66x of scale) sits inside the pre-registered 0.75 band — the band is untouched. Finding 2: the FSI3 release pin fired and the PIN was the finding. uy_mid (windowed mean over [4.0,4.2]) moved 44% (10.7684 -> 6.0229 mm) while amplitude (+7%), ux mid (+0.3%) and 5.2x growth all held; the baseline's 2 IQN history-reset retries became 0 — a rounding-level branch flip at unit density ratio (the traced bistable-mask sensitivity). The windowed mean of a growing 5-Hz oscillation is not a rounding-robust observable; its band now covers both measured branches (both recorded in the assertion), amp/ux re-centered at ±35%. New trajectory re-verified deterministic digit-for-digit twice before re-pinning; green in vivo under the new pins. Study-tier pins (FSI3 sticky-mask cycle, FSI2 s=1 benchmark cycle) re-verification launched; results to be recorded in solver_status.md. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-29 23:20:50 -05:00
Omar SobhandClaude Fable 5	8a8da2383d	rtx-fsi: wall-split instrumentation — the STRUCTURE is 79% of the coupled phase ... Per-pass timers (reporting-only, default digits verified identical) around the three pass components. Measured on the FSI3 committed default: fluid 99 s (19.7%), structure 397 s (79.2%), load sampling 0.9%, state save 0.0%. The flag's Newton step costs ~195 ms/pass against ~0.5 ms of element assembly and a ~10 ms-scale 570-DOF solve — either the stepper carries ~20x implementation overhead or the ROM upside is enormous; the ECSW campaign's re-scope decision inverts accordingly (profile the stepper next). Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-29 16:50:28 -05:00
Omar SobhandClaude Fable 5	50e382c046	rtx-fsi: ECSW phase-2 offline study — POD subspace confirmed, hyperreduction refuted at this resolution ... fsi3_ecsw_offline.rs (env-gated on RTX_ECSW_SNAP; committed default is a no-op) measures the three pre-registered quantities on the harvested run-7 flag trajectory, with a numbering self-check (clamped-DOF displacement exactly 0.0 across all 3,294 snapshots). Measured: (1) the flapping manifold compresses 560 free DOFs to 12-20 POD modes at ~0.5% held-out rms projection error — the subspace exists. (2) ECSW has NOTHING TO EXPLOIT on the 70-element flag: the NNLS residual sits at single-element scale until nearly every element joins (31 el -> 10%, 51 -> 10%, 67 -> 2.5%, 70 -> 1e-15; held-out == training everywhere; cycle-only manifold identical) — each macroscopic Quad8 carries non-redundant virtual work, so no sub-percent sample smaller than the mesh exists. (3) full reduced assembly 548 us/eval; ECSW at best 1.4x at a useless 10% residual. ReducedNonlinearModel gains assemble_reduced_force (the measured quantity). The campaign's >=10x structural gate cannot come from hyperreduction at the validated resolution — recorded in the campaign doc with the re-scope options. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-29 15:06:33 -05:00
Omar SobhandClaude Fable 5	d9d8801f1a	rtx-fea: mor gains total-Lagrangian operators and a held-out ECSW residual ... The mor scope was small-strain only ("geometrically linear") — a basis trained on total-Lagrangian trajectories (the FSI flag marches with_total_lagrangian) sampled through small-strain operators would conserve the virtual work of the wrong force. ElementOperator now carries a Formulation (SmallStrain | TotalLagrangian), the TL branch mirroring NonlinearDynamicAnalysis exactly (SVK from Lame parameters, total_lagrangian::internal_force_and_tangent); train_ecsw / ReducedNonlinearModel::new keep their behavior and delegate, with _formulated variants added. ecsw_residual evaluates a trained model's ||Cw - b||/||b|| on arbitrary snapshots — the held-out generalization measurement; on the training set it reproduces training_residual to 1e-12 (pinned). Verified sharply: identity-basis reduced TL solve vs a tight-tolerance full TL solve agrees to 4.4e-15 (machine precision) while small-strain operators land 1.1e-2 away at the same load — the switch is exercised and exact. (At the default 1e-6 convergence criteria the reference itself stops 1.7e-4 short; measured and recorded in the test comment.) Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-29 15:01:09 -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	a49602cf16	rtx-fsi: pin FSI3's release response and settled cycle ... Two tiers in the FSI2 pattern. The committed default (t_end 4.2) pins the deterministic release response at the digit-stable measurement (uy 10.7684 +- 23.5726 mm, ux -2.8982; +-35% bands, 2x onset-growth floor against a measured 4.6x). The sticky-mask study configuration (HYST>0, subcycle 2, t_end >= 8.4, ny 62 or 82) pins the settled flapping cycle measured across two grids at t_end 8.5 / window(2.0): uy amp in [38, 72] mm (measured 50.2 / 57.6; the un-flapped release and every pre-hysteresis dead march sit far below, and the reference +-34.9 sits OUTSIDE — landing inside the reference band is a loud finding, not a regression), mids, crossing-frequency in [4.4, 6.8] (covers the estimator's measured beat-scatter — the DFT puts both grids at 5.4-5.6 vs ref 5.46), and drag MEDIAN in [380, 530] (measured 454.0 vs ref 460.2). WindowStats gains drag/lift medians — the honest central loads (the extreme-based mids are noise-dominated at large deformation). Band anchors computed exactly as the test computes them, replayed offline against the run 7/8/10 CSVs (deterministic trajectories). Verified: both committed defaults green with the release pins live, trajectories digit-identical (FSI3's loads line gains the medians, FSI2's output byte-identical). The t_end 8.5 study pin runs at both grids are in flight. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-28 07:56:51 -05:00
Omar SobhandClaude Fable 5	137a62c4ea	rtx-fsi: time-resolved-honest load record — per-step sampling, interval median ... The reported drag/lift were one instantaneous measure_force sample every 10th coupled step, and the embedded-boundary surface force carries zero-mean sign-flipping fresh-cell pressure transients at step scale (measured: +-4,000-scale swings against a +-78 reference while displacements matched the benchmark to 0.1%, and the window MEDIANS sat near-physical). The record now samples the committed field every step and records the interval median — the estimator the CSV analysis supports; ten steps span 2-5% of a flap period, so nothing physical is smeared. Reporting only: measure_force reads the committed state. Verified on both committed defaults against pre-change logs — every displacement, conservation, and coupling digit identical; only the load lines moved, and toward the benchmark: FSI3 drag 628.66 +- 545.11 -> 443.26 +- 148.50 (ref 460.2 +- 27.47, mid now within 3.7%), lift amp 2289 -> 668; FSI2 lift amp 52 -> 28. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2	2026-08-27 14:58:17 -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	3207f2d4c6	rtx-fsi: decouple the retry threshold from the widened stall acceptance ... The first STALLX draft used one threshold for both, which silently disabled the history-reset retry for the widened band: a stall in [5x, STALLX x) was accepted unretried where runs 2/3 retried it — caught by trajectory divergence at t = 5.7 (runs 2/3 digit-identical there; the run-5 variant killed at 2.3 h, artifacts preserved as *_unretried_variant_*). Now `retry_at` stays the old 5x-or-increment window (retry semantics bit-identical to the pre-knob code at any STALLX), and `stall_accept` widens only the post-retry acceptance. Default STALLX=5 keeps both thresholds equal — committed defaults unchanged. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-25 07:41:34 -05:00
Omar SobhandClaude Fable 5	992cd76449	rtx-fsi: stall acceptance as a knob (STALLX) — the floor must stay tight; only the rare-event window widens ... FSI3's developed cycle stalls (bistable mask flips at max-velocity crossings) sit at 3.5e-4 against the measured floor 6e-5: run 3 died 16% over the 5x window at t = 7.70. Riding the FLOOR up instead was measured to make it worse — run 4 at floor 1e-4 died EARLIER (t = 6.30) at a HIGHER stall (1.2e-3, 2.4x its window), because the accepted-step scatter IS the wall-velocity noise (tol/dt_c): a looser floor feeds the flip noise it is trying to pass. Keep the floor tight and widen only the counted, bounded stall window: `stall_accept` (RTX_<CASE>_STALLX, default 5 — both committed defaults bit-identical). Precedent: FSI2's s = 1 benchmark run accepted a worst stall of 5.4e-4 the same way and measured 0.1% in amplitude. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-25 05:00:56 -05:00
Omar SobhandClaude Fable 5	647f247601	rtx-fsi: report Newton rescue counts in the coupling-failure panic ... FSI3 run 3 died on a coupling stall 0.2 s after the rescue carried it past run 2's Newton death, and the panic path printed nothing about how many rescues had engaged. Observability only — the panic message now carries rescue_counts. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-25 01:07:49 -05:00
Omar SobhandClaude Fable 5	d2c82af91b	rtx-fea: rescue the nonlinear Newmark Newton — line search, then step subdivision ... Both FSI3 study deaths were the flag's SVK Newton returning ConvergenceFailed{60} inside a coupling pass at a violent mid-cycle load. The plain full-step Newton stays float-op identical (FSI2 and FSI3 committed defaults re-verified digit-for-digit, Newton rescues (0,0)); only on failure does the stepper retry: a backtracking line search on ||R|| (Armijo, alpha down to 2^-29 — 2^-8 was measured too shallow when the tangent K_T + M/(beta dt^2) is near singular and the solved direction enormous and inexact), then 2/4/8/16 Newmark substeps of dt/n, each line-searched. Rescues are counted and surfaced through MarchResult and both FSI test printouts. Measured before writing (tests/newton_rescue.rs): a static tip load from rest NEVER defeats plain Newton (1e6 N converges in 19 its — from a quiescent state the predictor is the current configuration and M/(beta dt^2) regularizes the walk) — pinned as a negative result; the killer is a mid-swing load REVERSAL (1e4 N tip load, 3 steps of swing at dt 5e-3, then reversed: dead in 60 its), the FSI3 turning-point shape — now rescued by the line search alone and consistent with a dt/32 reference march of the same interval (-0.341 vs -0.195 m, same branch), with determinism (bit-identical re-step) and march-continuation pinned alongside. Also: pin the s = 1 FSI2 benchmark cycle at study horizons (iqn / subcycle 1, t_end >= 16: f in [1.85, 2.0], uy amp in [70e-3, 92e-3] — the mode-2 s = 2 cycle fails both bands, so losing the benchmark cycle stays loud). Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-24 19:14:13 -05:00
Omar SobhandClaude Fable 5	555a72cbc0	rtx-fsi: spike-clamp the force-measurement probe ... measure_force integrated raw traction samples while the coupling loads carried the 20x-median clamp — so the s = 1 benchmark run's REPORTED drag/lift were +-4,000-scale garbage against a +-78 reference while its displacements matched the benchmark to 0.1%. Collect, clamp, then integrate, both probes. Reporting only: the committed FSI2 default reproduces its trajectory to every printed digit (uy 3.7732 / 3.7920 mm) and its rigid-phase drag (121.4) with the clamp in. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-24 05:59:18 -05:00
Omar SobhandClaude Fable 5	c1bcdc408e	rtx-fsi: FSI3 floor 6e-5 — the floor rides with the motion; measure it through the cycle ... The first subcycle-2 study (t = 4 -> 8) ran 2.2 s of cycle — over [5, 6] s: +-42.8 mm at 6.2 Hz, trending toward the reference +-34.9 mm at 5.46 Hz from above — then stalled at t = 6.18 s: residual 1.9e-4 against an accept window of 1.5e-4 (5 x the 3e-5 floor the rest-state probe suggested), at a turning point of the cycle where the step increment, and with it the increment-relative part of the window, collapses while the flip noise does not. Floor set from the cycle's measured stall level (window 3e-4). Default re-verified: 581 steps, 3.5 subit/step (max 5), 0 stalls, conservation 1.5e-12, ux -2.90 +- 2.93 mm vs reference -2.86 +- 2.70. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-23 23:41:02 -05:00
Omar SobhandClaude Fable 5	c0666bf22a	rtx-fsi: C3 — FSI3 opened: the added-mass regime, its impulse artefact, and the coupler hygiene it demanded ... The march is extracted from the FSI2 test into a shared tests/fsi2_harness/march.rs (MarchConfig from env / MarchResult / window statistics), the harness parameterised by BenchmarkCase (FSI2, FSI3: inflow, solid density, modulus, rigid-flag drag reference), and turek_hron_fsi3.rs written on top (Re 200, density ratio 1, E 5.6e6). The committed FSI2 default is bit-identical through all of it — every new knob defaults to FSI2's behaviour; re-verified twice to every printed digit (uy 3.7732 / 3.7920 mm). FSI3's first contact, traced pass by pass (RTX_FSI3_TRACE), exposed the added-mass instability in its purest form and, one measured mechanism at a time, what a partitioned coupling at unit density ratio needs: - C^1 interface motion (MarchConfig::c1_interface): a constant per-step interface velocity is a velocity JUMP at each step start, and the incompressible fluid answers with an impulsive added-mass load ~ rho L dv / dt_fluid (8x the physical reaction under subcycling): 1,600 N at release, 48,000 N and a 59 mm response one step later, the flag's Newton dead the pass after. Constant acceleration from the previous end velocity to 2 dd/dt - v_n removes the impulse (loads 1,700-2,400 N). - IQN first-pass relaxation as a knob (initial_relaxation, FSI3 0.05): |1 - omega (1 + g)| must contract; 0.5 diverges past gain 3. - The divergence verdict waits for the secant (IqnIls): the exploratory second pass on a high-gain map legitimately overshoots 10x before the first secant column exists. Pinned by a gain-40 model test. - Kinematic predictor (predictor: "kinematic", velocity only): the structure-alone predictor ignores an added mass comparable to the flag's and overshoots 2-5x, drawing 5-6x loads every first pass; and NOT with the acceleration — Newmark average acceleration carries an inconsistent initial acceleration as a sign-alternating mode (d + dt v + dt^2 a / 2 predicted 22 mm at release; converged 0.14). - Quiescent release (quiescent_release): the structure-alone "consistent" initial acceleration M^-1 F ignores the added mass. - Coupler hygiene (IqnIls): a stalled or diverged step's secant columns are no longer retained (a bistable mask flip's columns extrapolated a 30 mm interface jump on the next step); two-window stagnation detection reports a plateau early instead of bouncing to the budget (a single-window test misjudged a slowly converging step and is recorded as such); trust region tightened to 10x the residual. A noise-column filter at the tolerance was measured to HURT (stalled a converging step at 5.5e-4) and is disabled (threshold 0). - The floor measured, not borrowed (fsi2_interface_noise.rs gains RTX_NOISE_CASE=fsi3): flip jumps 3.6e-4 (12x FSI2's), the subcycle-8 release map stalling near 1e-6, the subcycle-2 map converging to 9e-10; and through the release transient (flag at ~0.3 m/s) the subcycle-8 floor rides up to ~1e-3 with the motion — which moved the FSI3 default to subcycle 2 at a 3e-5 floor. FSI3 committed default (ny 62, release t = 4, t_end 4.2, subcycle 2): 581 steps, 3.8 subit/step (max 8), 0 stalls, 0 retries, conservation 4.3e-13; uy 10.1 +- 27.5 mm and ux -3.1 +- 3.2 mm over the first 0.2 s (reference cycle 1.45 +- 34.90, -2.86 +- 2.70). Machinery invariants pinned; physics bands await the study record. Rigid-flag drag 426.9 vs CFD3's 439.45 (-2.9%). The FSI2 mode-2 study pin (IQN / subcycle 2, t_end >= 16) was measured with the pre-hygiene coupler; re-verify on the next s = 2 study run. 48 lib tests green, clippy clean. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-23 19:43:02 -05:00
Omar SobhandClaude Fable 5	be04e0e233	rtx-fsi: pin the mode-2 flapping cycle under the IQN / subcycle-2 configuration ... Study horizons (t_end >= 16) under RTX_FSI2_COUPLER=iqn RTX_FSI2_SUBCYCLE=2 now assert the measured mode-2 cycle: frequency in [2.05, 2.45] Hz and uy amplitude in [45, 70] mm — bands that admit the settled cycle at either grid (ny=62: 57.6 mm / 2.227 Hz at t=16, 55.9 / 2.224 at t=30; ny=82: 57.1 / 2.236 at t=20) and reject both the wake attractor (3.73 Hz, ±17 mm) and the reference itself (1.93 Hz, ±82 mm) as material changes. The default configuration's pins are unchanged. Module docs brought up to the eleventh-session record. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-23 16:54:12 -05:00
Omar SobhandClaude Fable 5	a342e703a4	rtx-fsi: trust-region cap on the IQN step + increment-scaled stall acceptance ... The s = 1 FSI2 march (deepest rung: 1.955 Hz, ±73 mm mid-growth) found two coupler failure modes at peak motion: - run 1 (budget 12): NotConverged at residual 6.1e-4 = 9% of the step's own increment, after the history-reset retry — killed at t = 11.1 s. - run 2 (budget 30): the deeper budget let an ill-conditioned secant model extrapolate the locally violent map into a candidate interface that swept to the domain wall and crashed the mask build BEFORE any residual guard could fire (t ~ 9.9 s). Fixes, both scale-relative per the absolute-threshold rule: - STEP_CAP = 50: the full quasi-Newton step r + W alpha is capped at 50x the current residual norm, direction kept. Legitimate large Newton steps (near-marginal gains) pass; thousand-fold geometric extrapolations cannot. Pinned by a noisy-map test asserting every iterate's step stays within the cap. - The march accepts a stalled step at residual < max(5 x tolerance, 0.1 x the step's own increment) — the rare violent step near peak motion carries an order-below-increment error, counted like every stall and bounded by the existing stall-fraction assert; the retry trigger mirrors the same bound. 46 lib tests green, clippy clean. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-21 19:14:53 -07:00
Omar SobhandClaude Fable 5	d5f19ea497	rtx-fsi: IqnIls::reset_history — stale secant columns overshoot in rapid transients ... The s = 2 ladder march (resonant growth finally open: 2.3 Hz, amplitude through ±46 mm — 2.7x the wake attractor the loose coupling locked) died at t = 11.12 s with CouplingDiverged at iteration 2: the predictor left a 1e-4 first residual, and the first quasi-Newton update drove it to 1.1e-3. Cross-step secant history assumes the interface Jacobian drifts slowly; columns recorded at much smaller amplitude steered the least-squares direction wrong at 2.7x that amplitude, and the divergence guard read the overshoot as added mass. The map itself converges deeply from a clean start (the noise probe's stall measurement), so the recovery is: reset the history, retry the step once from the predictor. - IqnIls::reset_history(), with a cold-start-equivalence test. - turek_hron_fsi2: on an unaccepted coupling verdict under the IQN coupler, reset + one retry from the predictor (Aitken carries no history — a retry would repeat the identical iteration, so the path is IQN-only); retried steps counted and reported like stalls. Verified end-to-end: the re-run crossed the killing step and marched on (t = 11.18: uy +56 mm, window amp ±50 mm, 1.4 subit/step). 45 lib tests green, clippy clean. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-21 09:34:10 -07:00
Omar SobhandClaude Fable 5	140310b223	rtx-fsi: the noise floor interrogated — smoothing refuted, IQN-ILS lands, tight coupling reopened ... The tenth session ended on "lower the interface noise floor". This builds the levers and measures them, and the measurements overturn the diagnosis: - smooth_tractions: arclength moving average over the wetted surface, area-weighted, smooth normal-similarity factor so corners do not mix and the smoothed load stays continuous in the geometry. Nine unit tests. MEASURED NEGATIVE RESULT: the flip-scan floor is unchanged to 0.2% at radii 1-3h — the flip's load jump is coherent through the fluid field (mask rebuild shifts the pressure around the flipped cell), and a surface average preserves coherent shifts. Default off; the probe pins the attribution so nobody re-reaches for this lever. - IqnIls: interface quasi-Newton with inverse least squares (Degroote 2009) — filtered MGS least squares over secant columns (filter RELATIVE to column norm), cross-step history reuse, per-step set_tolerance. Model-map tests: exact on anisotropic linear maps within dim+2 passes (scalar Aitken provably cannot be), scale invariant, history reuse shortens the next step, stalls at the noise scale instead of diverging (fixture lesson: per-pass noise, not state-dependent noise — the latter has a genuine fixed point). - tests/fsi2_harness/: the FSI2 machinery extracted shared; verified pure code motion (committed release response reproduced to every printed digit). March gains RTX_FSI2_SMOOTH / RTX_FSI2_COUPLER=iqn / RTX_FSI2_REUSE knobs; pinned bands guard the default configuration. - tests/fsi2_interface_noise.rs: the probe. Flip-scan floor at subcycle 8: 3.05e-5 (pinned); smoothing attribution pinned; the cross-subcycle scan recorded but unpinned (the fixed geometry increment's wall-velocity trend, increment/dt_c, swamps the flip signal at small dt_c — a dt_c^2 scaling hypothesis died in that operationalization). THE OPERATIONAL FLOOR — the real release step subiterated at tolerance 1e-9 with residuals traced — converges DEEP at both subcycles: s8 aitken 3.4e-9 / iqn 1.6e-9, s2 both ~6.4e-10 in 5-6 passes. The flip jumps are events at specific geometries, not a floor under every step: the tenth session's subcycle-2 blowup was tolerance mis-budgeting (2e-4 held fixed while dt_c shrank), not an impassable floor. Probe bug found and fixed on the way: stale shared geometry leaked a 4.5e-5 phantom first residual into the first stall run; every measurement now resets the geometry on entry. All 924+17 tests green: lib 44 (was 27), piston 2, curved edge 1, FSI1, the committed FSI2 march (release response identical), the probe. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-21 06:42:05 -07:00
Omar SobhandClaude Fable 5	4e90177aa9	rtx-fsi: C2 — FSI2's coupled march, and the wrong attractor measured ... The unsteady coupling on the piston pattern with the real solvers: per TIME STEP, Aitken subiterations of (8x-subcycled embedded TVD/multigrid fluid <-> flag nonlinear-Newmark step), the fluid re-runnable through snapshot/restore + a field clone, the flag re-runnable because the stepper commits nothing, the moving polygon carrying the flag's actual interface velocity. Conservation 8.3e-12 over 9,263 coupled steps; the rigid phase reproduces this solver's own CFD2 values at both grids before anything couples. What the 30 s studies measured (ny = 62 AND 82, three protocols): the coupled system self-excites into a wake-forced cycle at 3.729/3.728 Hz with uy(A) +-17.3 mm at both grids - grid-converged, protocol- independent, kinematically genuine (ux locks 2x uy) - and NOT the benchmark's mode-2 resonant cycle (1.93 Hz / 81.6 mm; the flag's vacuum mode 2 is 1.9245 Hz). Diagnosis measured stepwise: the staggered phase lag starves the resonant channel (a subcycle=2 probe redirected growth to 1.9 Hz as predicted), and tighter dt_c is blocked because wall- velocity noise = displacement-tolerance / dt_c while the needed tolerance sits below the discrete interface noise floor (~1.3e-4 at full inflow, mask flips through beta dt^2/m). The route to the benchmark cycle is lowering that floor, not iterating against it. Robustness, both measured: rare wild tractions (19 samples in 2.4M) clamped at 20x the sample median - clamped, not dropped: a hard drop makes the pass discontinuous and the subiteration bounces at step scale; and Aitken "divergence" verdicts within 5x tolerance accepted as noise bounces over well-predicted steps (counted, bounded). The committed default (t_end = 7, ~9.5 min) pins the deterministic release response (uy 3.773 +- 3.792 mm, band +-35%); study horizons >= 25 s pin the measured 3.73 Hz attractor so any material change is loud. Full study record in the module docs and omni-cortex solver_status.md. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Lnyrw33Lu6rUhW42E9KHwq	2026-08-21 02:45:43 -07:00
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	b82f307cae	rtx-fsi + rtx-cfd + rtx-fea: FSI1 — the coupled cylinder and flag ... The summit rung C1: all the verified pieces joined into the first coupled Turek–Hron computation (rtx-fsi/tests/turek_hron_fsi1.rs). The embedded fluid computes tractions on the DEFORMED flag surface (EmbeddedMask::traction_at, factored from surface_force); the flag's wetted boundary is a polygon whose vertex list sits behind a lock, so the moving-body mask rebuild picks up every shape update (EmbeddedBody::polygon + pub polygon_signed_distance); WettedSurface — rebuilt on the deformed interface every subiteration — carries the loads to the flag's boundary nodes (NonlinearStaticAnalysis::set_nodal_forces); Subiterated::aitken drives the exchange, each pass marching the fluid to flag-load stagnation so the coupling map is a function of geometry, not of the fluid's transient. Result (ny = 62, 6 Aitken passes, 420 s): coupled drag 15.360 (+7.5%, the rigid CFD1 band at this grid), lift 0.7977 (+4.4%), ux(A) 2.647e-5 vs 2.270e-5 (+16.6%; +6.1% at ny = 82), uy(A) 3.90e-4 vs 8.21e-4 at h = 6.6 mm and 1.124e-3 (+37%) at h = 5 mm — the resolutions BRACKET the reference through the flag's 3 -> 4-cell thickness transition, like the rigid-flag lift; conservation 7.4e-12 every pass. Bands asserted are the measured ones; RTX_FSI1_NY runs studies. Two real rtx-fsi defects found by this rung (15th and 16th of the campaign), both regression-tested (tests/transfer_curved_edge.rs): 1. solve_weights built its constraint Gram from RAW coordinates: the condition number grows as (position/spacing)^2 — ~1e4 for a flag edge at x ~ 0.26 with 5 mm spacing — and the 4x4 SVD pseudo-inverse lost enough accuracy that the (correctly strict) partition-of-unity / reproduction verification rejected healthy neighbourhoods: the operator's behaviour depended on WHERE the interface sat. Now centred on the face and scaled by the neighbourhood radius — identical constraints, O(1) conditioning, translation-invariant. 2. A NEARLY collinear neighbourhood (the nearest nodes of a face on a smoothly deformed edge: y is almost linear in x, off by the curvature sagitta) cannot satisfy exact centroid reproduction with bounded weights — the offending singular value is too large to truncate and too small to invert. The recruitment now widens (8 -> 16 -> 32 -> all) until the verified constraints hold; for a thin structure that pulls in the opposite face, exactly the transverse spread the system needs. Findings measured before believed: the transfer is faithful (a strictly local two-node split of the same tractions moved the tip by 2%); the uy error is the sampled lift PROFILE on a 3-cell flag (a uniform distribution of the same net lift bends 4x more), confirmed by the resolution study; TVD limiter chatter (+-0.5% steady load — limited schemes stall short of machine steady state) defeats steady fixed-point coupling, so steady coupled cases run upwind while the time-marched FSI2/FSI3 keep TVD; and the mask never chattered at FSI1's sub-cell amplitude (fluid-cell count constant through every pass). rtx-fsi 29 -> 31 green (lib 27, piston 2, curved-edge 1, FSI1 1). Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 17:22:27 -07:00
Omar SobhandClaude Fable 5	38ca5ef080	rtx-fea: S2 — nonlinear Newmark, and Turek–Hron CSM3 to 0.1–1.3% ... analysis::nonlinear_dynamic::NonlinearDynamicAnalysis: Newmark-beta with a full Newton solve on the internal force inside every step — residual F_ext − f_int(u) − M a(u), consistent Jacobian K_T(u) + M/(beta dt^2), the same total-Lagrangian St. Venant–Kirchhoff / small-strain seam the nonlinear static analysis uses, consistent mass assembled once (element mass is configuration-independent in a total-Lagrangian setting), undamped, homogeneous Dirichlet only (prescribed interface motion arrives with the FSI rung). The existing NewmarkStepper stays what it is: the right tool for constant matrices. Verified (tests/nonlinear_newmark_csm3.rs): - linear limit (strains ~1e-9): the TL nonlinear stepper reproduces the verified linear NewmarkStepper on the same dense M, K, F to a max deviation of 1.7e-16 — 1.3e-9 of the oscillation amplitude — over 120 steps; - Turek–Hron CSM3 (35x2 Quad8, dt = 0.005, gravity switched on at rest, 6 s): ux(A) = −14.291 ± 14.291 mm vs the reference −14.305 ± 14.305 (0.1%); uy(A) = −63.644 ± 64.295 mm vs −63.607 ± 65.160 (0.06% mean, 1.3% amplitude); frequency 1.1020 Hz vs 1.0995 (0.23%); two Newton iterations per step throughout; the undamped amplitude persists (half-window drift 0.2%). rtx-fea 564 -> 566 green (full suite). With this the S-side of the Turek–Hron ladder is complete: statics (CSM1/CSM2) and dynamics (CSM3) both land on the benchmark. Next rung is the coupling: FSI1 with the embedded fluid, the TL flag, and rtx-fsi's transfer rebuilt on the deformed interface each subiteration. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 14:02:15 -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
Omar SobhandClaude Fable 5	35b2b2cdf4	rtx-cfd: TVD convection in the embedded predictor — the wake sheds — and Turek–Hron CFD2/CFD3 ... First-order upwind's numerical viscosity |u| h / 2 is ~10x the physical viscosity on the Turek–Hron grids: the effective Reynolds number lands near 20 and CFD3 (Re 200) produced NO vortex shedding at all — one lift zero-crossing in three seconds at h = 10 mm. The physics, not a bug. EmbeddedParameters gains `convection_scheme` (default Upwind, bit- identical — the no-body degeneracy test still reads 0.0): the TVD branch adds SIMPLE's limited face corrections (van Albada / van Leer, `face_correction` now pub(crate)) directly in the explicit predictor — no deferred iteration needed in an explicit step. Domain-side faces and faces whose far-upwind node is outside fall back to upwind exactly as in SIMPLE; near the body the stencil reads ghost values, which encode the wall. Verified: the embedded-circle MMS error drops 10–16x below upwind (8.16e-4 vs 8.49e-3 at n = 32) at observed order 1.56 (SIMPLE's TVD measured 1.59–1.84). tests/turek_hron_cfd23.rs — CFD2 (Re 100, steady) and CFD3 (Re 200, periodic), both with the benchmark's inflow ramp, both measured as time statistics over a window (never a snapshot), surface route primary and the control volume printed as the diagnostic (its central-difference evaluation truncation grows with the convective flux: the routes agree to 0.6% at Re 20 and differ 15–25% at Re 100–200 on these grids). Measured across h = 10 / 6.6 / 5 mm: - CFD3 shedding frequency 4.2746 / 4.3400 / 4.3939 Hz vs the reference 4.3956 — converging −2.8% -> −1.3% -> −0.04%; - CFD3 lift mean −184 / +160 / −2.6 vs −11.9 — lands on the reference; lift amplitude ±438 / ±556 / ±557 vs ±437.8 — +27% at the finer grids, unconverged (the flag is 2/3/4 cells thick); - CFD2 control-volume drag 152.4 / 143.3 / 139.4 vs 136.700 — +2.0% at 5 mm; CFD2 surface drag sits ~−10% (the boundary layer is ~one cell); CFD2 lift −3.4 / +30.2 / +8.4 vs 10.53. Suite defaults run CFD2 at ny = 62 and CFD3 at ny = 41 (cost); the asserted bands are the measured ones (frequency 10%, mean drag 15%, amplitude 35%), not accuracy claims; RTX_CFD2_NY / RTX_CFD3_NY run the studies. Also recorded: the CFD1 refinement study extended to h = 3.3 mm (RTX_CFD1_NY): control-volume drag 14.8996 (+4.25%), apparent order ~0.70 sustained over four grids, control-volume lift 1.1332 vs 1.11905 (+1.3%). rtx-cfd 318 -> 321 green (full suite 321 passed / 0 failed). Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 11:37:04 -07:00
Omar SobhandClaude Fable 5	327da7ff47	rtx-cfd: multigrid-PCG projection — 30x faster, same answers — and the CFD1 refinement study ... Falsifier 4 of the Turek–Hron geometry decision fired (the SOR projection cost 0.09 s/step at 250x41 and an hour per run at 5 mm); this answers it. solvers::incompressible::poisson: PoissonProblem (cell-centred five-point SPD operator as per-cell face coefficients + Dirichlet diagonal extra + active mask) and solve_multigrid_pcg — conjugate gradient preconditioned by one V-cycle of geometric multigrid: aggregation by 2 per direction (odd sizes absorbed, coarse cell active iff any child is), the Galerkin coarse operator for piecewise-constant prolongation / summation restriction, symmetric Gauss–Seidel smoothing, coarse correction scaled by 2 (Braess's under-correction of unsmoothed aggregation; scalar, so the preconditioner stays symmetric and positive on range(A)), L1 TRUE-residual stop with a stagnation guard. Singular systems are handled per connected component of the active cells (mean projection and level per pure-Neumann component; the anchor's component to p[anchor] = 0). PoissonSolverKind::{Sor, Multigrid} on PisoParameters / EmbeddedParameters; Sor is the default and its code is byte-for-byte untouched; an unconverged multigrid solve falls back to the SOR sweeps for that projection. Verified (poisson/tests.rs, tests/poisson_equivalence.rs): - PCG iterations to cut the residual 1e-8 on the closed Neumann box at 32^2..256^2: 4, 4, 4, 4; ragged masked domains 8/8/8; - manufactured recoveries to ~1e-14; Galerkin identity A_c v = R A P v to 7e-15 on every level (masked, outlet column, non-uniform conductances); V-cycle symmetric to 1e-14; NaN-poisoned inactive cells untouched; - two Neumann components with opposite imbalances, and a Dirichlet component beside an imbalanced Neumann one (review scenarios): converge, each component right up to its own constant; - speed vs plain SOR at the same stop: 22.7x (128^2), 41x (256^2); - same answers as SOR: PISO MMS 4.6e-8 relative, Taylor–Green divergence 1.4e-9 every step, embedded-circle MMS 7e-8, no-body bit-identity with MG on both solvers, channel+outlet+circle 1.4e-10; CFD1 loads identical to four digits at 0.003 s/step vs 0.094 (30x). CFD1 refinement study (tests/turek_hron_cfd.rs, three grids, 257 s): h = 10 / 6.6 / 5 mm -> control-volume drag 15.6156 / 15.2829 / 15.0988 vs 14.2929 (+9.25 / +6.93 / +5.64%), apparent order 0.71, Richardson extrapolate 14.04; surface route and lift not monotone (flag 2/3/4 cells thick) — the test asserts the measured band at the finest grid. Built with a 4-agent workflow (core, integration, refinement study, adversarial review); the review found no defects and four risks, three fixed here (per-component projection, one symmetric smoother-sweep parameter, acting on `converged` with an SOR fallback) and one recorded (isotropic aggregation loses grid-independence on anisotropic cells). rtx-cfd 301 -> 318 green. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 10:20:25 -07:00
Omar SobhandClaude Fable 5	c25f15b3c4	rtx-cfd + rtx-fea: embedded-boundary PISO and total-Lagrangian SVK — the first two Turek–Hron rungs ... The Turek–Hron geometry decision (omni-cortex docs/turek_hron_geometry_decision.md) chose an embedded boundary on the fixed Cartesian MAC grid over body-fitted unstructured ALE; this commit builds the first rung on each side of the ladder, verified MMS-first. rtx-cfd — solvers::incompressible::{embedded, embedded_body}: EmbeddedPisoSolver is the fixed-grid PISO predictor/projection with per-side domain boundaries (ALE's SideBoundary semantics, so the channel has an outlet), a (x, y, t) boundary-velocity function, and an optional EmbeddedBody (signed distance + surface velocity; circle / rectangle / union). EmbeddedMask classifies cells (fluid iff phi > 0 at the centre) and faces (fluid iff both cells fluid; ghost within 1.5 h; solid deeper); the predictor updates fluid faces only, the projection enforces continuity on fluid cells with zero coefficient across prescribed faces, ghost faces are re-imposed after each projection from a boundary-intercept least-squares linear fit (exact for linear fields), the net ghost mass flux is removed uniformly so a Neumann projection stays compatible, and loads come by two routes: surface-stress reconstruction (full viscous traction) and a control-volume momentum balance. Verified (tests/embedded_mms.rs, tests/turek_hron_cfd.rs): - no body, closed box: bit-identical to PisoSolver over 200 steps; - embedded off-centre circle MMS 16/32/64: velocity orders 0.92, 0.97 (plain PISO 0.85, 0.91), pressure 0.96, 0.90, max |div u| <= 9e-8 on every fluid cell, compatibility correction 6e-4 -> 3e-5; force on the circle vs the exact surface integral: surface route 0.52 -> 0.29 -> 0.15, control-volume route 0.61 -> 0.30 -> 0.15 (both first order, two unrelated readings of the same solution); - Turek–Hron CFD1 (Re 20, h = 10 mm, flag two cells thick), settled to four digits: surface drag 15.71 / lift 0.94, control-volume drag 15.62 / lift 1.08 vs reference 14.29 / 1.119 — the drag routes agree to 0.6%, both +9.5%. A coarse first number; the refinement study waits on a multigrid projection (SOR: 0.1 s/step at 250x41 in the test profile). Fourteenth defect of the campaign: the fixed-grid PISO predictor zeroes the transverse convective face velocity on its domain sides (exact for walls); carried into a solver with an outlet it dropped the OUTGOING momentum flux through the outlet side of the v control volumes, the last column accumulated, and CFD1 went NaN at t ~ 4 s. Found by printing where max |u| lived (x = 2.5) after halving dt changed nothing. Fluxes now come from the stored boundary faces on every side. rtx-fea — elements::total_lagrangian + NonlinearStaticAnalysis:: with_total_lagrangian(): Green–Lagrange strain, second Piola–Kirchhoff stress from a St. Venant–Kirchhoff law on the material's Lamé parameters (plane strain in 2-D), B_L of the current deformation, material plus geometric tangent; dead-load body force per reference volume. Verified (tests/total_lagrangian_svk.rs): - zero displacement: the plane-strain stiffness to 1e-13; - tangent = d f_int/du by central differences at 20% random displacement (Quad4, Quad8, Hex8): relative < 1e-7, symmetric to 1e-12; - a 34-degree rigid rotation produces no internal force; the small-strain routine does (negative control); - manufactured finite-strain solution, body force by FD of the exact P = F S: Quad4 orders 1.95, 1.98; Quad8 2.93, 3.03, 3.02 (an 8% amplitude, Green–Lagrange strain to -0.25 near SVK's compressive limit E = -1/3, broke Newton on fine meshes — the material, not the code; 3% is clean); - Turek–Hron CSM1 at 70x4 Quad8: u(A) = (-7.060, -65.43) mm vs (-7.188, -66.10), 1.0% / 1.8%, converging from below (35x2: -65.14); CSM2: (-0.4604, -16.79) vs (-0.4690, -16.97), 1.1% / 1.8%. rtx-cfd 293 -> 301 green (5 unit + 3 integration), rtx-fea 559 -> 564. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 08:51:32 -07:00
Omar SobhandClaude Fable 5	4bd98b5264	rtx-cfd + rtx-fsi: the added-mass piston — partitioned FSI on the real ALE fluid ... The first coupled fluid-structure computation in the workspace, verified against a closed form, and the first time rtx-fsi's added-mass claims run against a real discretised fluid rather than a linear model map. ALE extensions: per-side boundaries (Velocity / SlipWall / PressureOutlet) and moving boundary lines. A moving Velocity side is a material wall whose prescribed normal velocity must equal the line's own motion; a pressure outlet takes Dirichlet p' = 0 in the projection (replacing the Neumann anchor) with a zero-gradient predictor on its faces. Fluid half verified alone (tests/ale_piston_channel.rs): prescribed piston motion, slip walls, outlet. The incompressible rigid column is exact DISCRETELY - continuity forces every u to the wall's discrete velocity (8e-12) and the projected pressure is exactly linear with gradient rho times the wall's backward-difference acceleration (2.5e-9). Coupled benchmark (rtx-fsi/tests/piston_added_mass.rs): elastic piston (Newmark average acceleration) against added mass rho*L*H at mass ratio 6.25, rtx-fsi's Subiterated driving a real fluid/structure pass per step: - plain staggered diverges in 7 subiterations (Causin-Gerbeau-Nobile on a real solver); - Aitken converges at 3.0 subiterations/step onto T = 1.07009 vs the closed form 1.06999 - 9.8e-5 relative, halving with dt; - outlet flux matches the piston sweep to ~1e-9 every step. Discrete-analysis finding: Newmark beta scales the staggered added-mass threshold - the iteration gain is beta*m_a/(M + K*beta*dt^2), so the continuous ratio 2.5 CONVERGES at beta = 1/4 (gain 0.625, measured ~17 passes/step) and the benchmark needs ratio 6.25 (gain 1.56). Two real defects found and fixed, twelfth and thirteenth of the campaign: 1. rtx-cfd ale::advance re-stamped boundary faces at t_old from the current boundary function, which in a coupling loop carries the NEW interval's wall velocity - the predictor's old state had interior u = w0 but wall face u = w1, leaving an O(dt) pressure artifact confined to the wall-adjacent cells (p exact to 6e-11 everywhere except the wall cell at 4.7e-5). The start-of-step boundary faces are whatever the previous step's end-of-step application left there. 2. rtx-fsi aitken_factor guarded its denominator - a SQUARED residual- difference norm - against a bare f64::EPSILON, silently disabling Aitken below residual ~1e-8 and degrading to unit relaxation exactly in the well-converged regime; the repulsive fixed point then amplified 1e-9 residuals back up and the coupling diverged. Third instance of the absolute-threshold species (NNLS, ECSW). The guard is relative now; aitken_is_scale_invariant pins it at initial residual 1e-9. rtx-cfd 293 green (+1), rtx-fsi 29 green (+3). rtx-fsi's lib gains only the relative guard; the coupling layer still depends on no solver (rtx-cfd is a dev-dependency of its tests). Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 06:10:13 -07:00
Omar SobhandClaude Fable 5	259c5baa63	rtx-cfd: ALE on a moving tensor-product grid, DGCL-exact by construction ... The first brick of the Turek-Hron frontier: PISO (explicit conservative predictor + SOR projection) generalised to a staggered grid whose x- and y-lines move arbitrarily each step while the domain boundary stays fixed. The discretisation choice that carries everything: time-averaged face areas (A^n + A^{n+1})/2 in both the fluid fluxes and the face-swept volumes. For tensor-product motion the discrete geometric conservation law then holds as an algebraic identity, so uniform flow is a machine-precision fixed point, not a truncation-order one: - DGCL test: uniform (0.7, -0.4) on a 16x12 grid with interior lines wiggling out of phase, 400 steps: max deviation 7.9e-15 (~35 ulp). Negative control with end-of-step areas (per-step cell error exactly dw*dh/V, the cross term the identity absorbs): 1.5e-2 - a 1e12 separation, so the test can fail. - Degeneracy: zero motion on a uniform grid vs fixed-grid PISO over Taylor-Green steps: max difference 2.2e-16 - one ulp - pinning every geometric generalisation to the verified implementation. - Physics under motion: Taylor-Green on the wiggling mesh, L2 error 2.42e-2 -> 1.07e-2 (n=16 -> 32, order 1.17); moving-mesh error at n=32 sits below the fixed-mesh 1.1532e-2 (PISO's published value to four digits); energy decay unchanged by the motion. One trap documented in the test: the projection's inner-stop floor (0.1 * tolerance * reference_flux) at an engineering tolerance lets a one-sweep partial p' accumulate into p, whose gradient perturbs the velocities at ~1e-11 with the geometry blameless. The DGCL run must use a rounding-level tolerance because machine-precision preservation is the claim under test. Measured: 3.6e-11 at tol 1e-9, 7.9e-15 at 1e-13. Incompressibility needs no mesh-velocity term: subtracting the GCL from moving-cell mass conservation leaves plain div(u) = 0 on the current geometry, so the projection is the fixed-grid one with non-uniform coefficients. 292 rtx-cfd tests green (288 + 4). Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 05:31:12 -07:00
Omar SobhandClaude Fable 5	8071d5888d	rtx-fea: ECSW model-order reduction — POD-Galerkin plus hyper-reduction, verified end to end ... The third Farhat gap. New rtx_fea::mor module: - pod::pod_basis — orthonormal SVD basis with an energy-criterion truncation. Verified: rank-2 data yields exactly 2 orthonormal modes that reconstruct every snapshot to machine precision; a loose tolerance truncates a dominant-mode-plus-noise set to one mode. - nnls — Lawson-Hanson non-negative least squares with the early stop that makes ECSW work: iteration ends at the requested residual, and the active-set structure caps the support at one column per outer iteration, so sparsity falls out of the stopping tolerance. Verified against KKT conditions, exact positive solutions, negative-clipping, and a sparsity-vs-tolerance case. Its thresholds are RELATIVE to the problem's own scales — the first version used absolute cutoffs (1e-14) that silently ended the iteration on ECSW's small-magnitude training systems at 1.2e-3 instead of the requested 1e-4. - ecsw::train_ecsw — element weights such that a small subset reproduces the reduced internal force (the virtual work against the basis) over the training snapshots. w = 1 solves the system exactly by construction, so it is always consistent; nonnegativity is what keeps a sampled element from producing energy. - reduced::ReducedNonlinearModel — Newton in POD coordinates, assembling either every element (POD-Galerkin) or the ECSW sample, on the same per-element force/tangent machinery the nonlinear analysis uses. End-to-end verification (tests/ecsw_mor.rs): a clamped nonlinear block, snapshots from a 4-point load sweep, evaluated at an UNSEEN load factor: POD modes: 2 ECSW sample: 5 of 24 elements training residual 2.2e-7 (requested 1e-4) error vs full solve: POD-Galerkin 3.09e-7, ECSW 3.08e-7 hyper-reduction cost (ECSW vs full ROM): 1.6e-8 And the assertion with the most teeth: the same 5 elements with their weights forced to 1 read a relative error of 1.22 — a completely wrong field — so the accuracy is carried by the WEIGHTS, not by the subset happening to be representative. Scope, stated plainly: geometrically linear, materially nonlinear, homogeneous Dirichlet only (no lifting); the basis lives on the free DOFs. 559 rtx-fea tests, 0 failing. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 00:43:32 -07:00
Omar SobhandClaude Fable 5	b321a9aba7	rtx-cfd: Taylor-Green validates PISO's transient path — and fixes the projection's inner solve ... With k = pi the decaying Taylor-Green vortex has zero normal velocity on the unit box for all time, so it fits the closed staggered domain exactly, with ZERO body force: convection is balanced identically by the true TG pressure and the decay comes from viscosity alone. This exercises exactly what the steady MMS harness cannot see — the time derivative, the unsteady pressure coupling and the projection's splitting error. The time-decaying tangential wall velocity enters by re-setting the wall hook each step. Measured (16/32/64, dt ~ h^2): L2 velocity 2.267e-2, 1.153e-2, 5.841e-3 — orders 0.97 and 0.98, first-order upwind's rate — and the kinetic-energy deficit against the exact e^(-4 nu pi^2 T) halves per refinement (0.0690, 0.0360, 0.0185; ratios 1.92, 1.95), within 2.3% on the finest mesh. Every step divergence-free to ~1e-7. Its first run caught two defects in the projection's inner solver: - The inner Gauss-Seidel stop summed the per-sweep iterate CHANGE — the same movement-not-residual pseudo-criterion the SIMPLE census flagged: slow modes move little per sweep while their residual is still large. - Plain GS contracts smooth modes by only 1 - O(h^2) per sweep, so the 400-sweep cap left max |div u| ~ 1e-2, GROWING with mesh size (8e-3 at 16^2 to 2e-2 at 64^2). The inner stop now measures the true equation residual, the sweep is SOR at the optimal Poisson factor omega = 2/(1 + sin(pi h)), and it converges relative to each projection's own source with a floor tied to the outer mass tolerance — so a long steady march no longer burns a hundred sweeps per step polishing negligible corrections. The steady MMS harness had masked all of this: a march to steady state iterates the projection to death regardless, which is why its divergence read 1e-9 while a 205-step transient left 1e-2. mms_piso's steady-state criterion is 1e-6 (was 1e-7): per-step projection noise at the mass tolerance floors |du/dt| just below 1e-6, and the L2 errors under measurement are 1e-2 to 1e-3. Its results are unchanged to six figures and still match SIMPLE's. 288 rtx-cfd tests, 0 failing. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 00:35:06 -07:00
Omar SobhandClaude Fable 5	d8a30db155	rtx-cfd: Ghia Re=400 as a quantitative claim — and the stopping-tolerance trap ... The Re=400 lid-driven cavity, 128^2 TVD on an exactly-unit domain, sampled on the staggered faces that lie exactly on the centrelines, against Ghia, Ghia & Shin (1982) — reference values sourced from two independent transcriptions that agree digit for digit (Mramor/Vertnik/Sarler CMC 2013 Table 1, and the ivan-pi benchmark collection): u_min -0.32667 at y = 0.2852 (Ghia: -0.32726 at 0.2813 — 0.18%) v_min -0.45024 at x = 0.8633 (Ghia: -0.44993 at 0.8594 — 0.07%) v_max 0.30044 at x = 0.2305 (Ghia: 0.30203 at 0.2266 — 0.53%) max |u - Ghia| over 15 profile stations: 0.0051 Ghia's own values carry ~0.3% discretisation error (Sahin & Owens 2003 put u_min at -0.32838), so this is at the reference's own accuracy. The finding worth the commit message: the first run used the Re=100 test's residual tolerance of 1e-4 and read u_min = -0.31987 — "converged", 2.3% shy — and refining to 192^2 made it WORSE (-0.30879, profile deviation doubled from 0.034 to 0.074). The residual had dropped below tolerance while the field was still developing, and the effect grows with mesh size because SIMPLE's per-iteration contraction weakens as h -> 0: at fixed residual tolerance the finer mesh stops at an EARLIER stage of convergence. Tightening the stop (3e-5, then 1.5e-5, until the movement per halving fell below the reference's own error) was the fix, and the test's bands are set so the premature-stop state fails all of them. "The residual converged" must never stand in for "the answer stopped moving". Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 23:23:32 -07:00
Omar SobhandClaude Fable 5	4da70faa1e	rtx-fea: QM6 as an opt-in bending path; cantilever pinned to Euler-Bernoulli directly ... The QM6 incompatible-modes stiffness existed and was verified (compute_stiffness_matrix_incompatible) but nothing could reach it: the assembler always routed Quad4 through the compatible element. AssemblyOptions gains use_incompatible_modes (default false — every existing matrix is byte-identical, which the manufactured-solution verification depends on), threaded through GlobalAssembler into StandardFiniteElement; element types QM6 does not apply to keep their standard stiffness either way. What it buys, measured on the cantilever first bending mode against Euler-Bernoulli's 40.3848 Hz: mesh QM6 (error) compatible (error) 8x2 40.4020 (+0.04%) 81.8102 (+102.6%) 16x4 40.3402 (-0.11%) 53.8022 (+33.2%) 32x8 40.3242 (-0.15%) 44.0796 (+9.2%) The frequency is now asserted against the closed form directly (0.5% band) instead of as convergence-from-above, plus the condensation theorem — QM6 can only soften, so its frequency must sit at or below the compatible one on every mesh. The slight undershoot on finer meshes is physical: the 2-D solid carries the transverse shear flexibility the beam theory neglects. 552 rtx-fea tests, 0 failing. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 19:47:25 -07:00
Omar SobhandClaude Fable 5	6510045b5d	rtx-fea: wire NonlinearStaticAnalysis — Newton on the consistent tangent, MMS-verified at second order ... NonlinearStaticAnalysis::run returned DVector::zeros unconditionally, like ModalAnalysis and DynamicAnalysis before their repair. It is now full Newton-Raphson on R(u) = f_ext - f_int(u): - ElementMatrixComputer::compute_internal_force_and_tangent integrates f_int = int(B' sigma dV) and K_T = int(B' D_T B dV) in ONE quadrature sweep from a constitutive closure in the element's reduced Voigt space — computing both together is what keeps the tangent consistent with the stress, which is what quadratic convergence rides on. - materials::reduced_constitutive bridges the Material trait (Voigt-6) to that closure: 3-D passes the total strain straight through; 2-D supports the linear plane-stress closed form and refuses nonlinear materials explicitly, since plane-stress condensation of a general law needs a per-point iteration that is not implemented yet. - Dirichlet DOFs are held at their (load-scaled) values and Newton runs on the free DOFs, so the prescribed motion enters through f_int itself — no K_fc bookkeeping to get wrong. Body force enters via set_body_force, the same hook pattern the CFD solvers use for manufactured solutions. Uniform load stepping; other strategies and quasi-Newton refuse explicitly. - StandardFiniteElement::compute_internal_forces, previously a zeros stub, now delegates to the same machinery. - Mesh::validate is now called in run() (the old TODO), and NonlinearConfig gained a Default. Verified two ways (tests/nonlinear_static.rs): - Equivalence: with LinearElastic the loop lands on the directly assembled linear solution to 1e-10 in exactly one Newton step — same B, quadrature and solver, so any disagreement is the nonlinear assembly. - Manufactured solution with a genuinely nonlinear material (energy W = 1/2 e'De + alpha/3 I1^3, so stress and tangent are exact derivatives; body force by central differences of the closed-form stress): L2 errors 6.032e-2, 1.780e-2, 4.595e-3 on 2/4/8 Hex8 — observed orders 1.76 and 1.95, climbing to the theoretical 2. The forcing contains the nonlinear term, so the order is reachable only if it is solved; an inconsistent tangent is caught separately by the iteration-count bound. This unblocks ECSW model-order reduction, which needs a working nonlinear solve underneath it. 551 rtx-fea tests, 0 failing. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 19:44:08 -07:00
Omar SobhandClaude Fable 5	e94ad1be6b	rtx-cfd: Poiseuille closed-form validation with exact-zero assertions ... Plane channel driven by a uniform body force: u(y) = G/(2mu) y(1-y), v = 0, p exactly constant. Convection vanishes identically, so this isolates diffusion, the half-cell wall treatment and the pressure coupling — and two of the three answers are exact zeros, which no benchmark comparison offers. The ends are clamped to the profile the DISCRETISATION prefers — the 1-D tridiagonal with half-cell wall closures, solved directly in the test — rather than to the continuous parabola. That makes (u_hat, 0, const) an exact fixed point of the 2-D discretisation, and the solver must sit on it: |u - u_hat| ~ 1e-10, max |v| ~ 1e-10, p spread ~ 8e-10 (16^2) A first version clamped the ends to the continuous parabola instead; the O(h^2) incompatibility between that profile and the discrete one drove a weak secondary flow near the ends (max |v| = 1.3e-3) — a property of the mismatched boundary data, not of the solver, recorded in the test docs so nobody rediscovers it as a bug. The wall treatment's own truncation is measured in isolation as |u_hat - parabola|: 3.906e-3 at 16, 9.766e-4 at 32 — refinement ratio exactly 4.00, second order, in closed form c h^2 / 4. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 19:32:37 -07:00
Omar SobhandClaude Fable 5	9b097fca0d	rtx-cfd: PISO validated by manufactured solution — after fixing the inverted projection ... PisoSolver was the only major solver in the workspace with no verification of any kind. Writing the MMS harness for it (tests/mms_piso.rs) and inspecting the implementation found the census's defect species again: - The pressure correction had its SIGN inverted: it solved -lap(p') = +rho div(u*)/dt and then corrected with u = u* - (dt/rho) grad(p'), so each projection DOUBLED the divergence instead of removing it. - The momentum sweeps froze the near-wall lines (1..ny-1) and the pressure correction skipped the outer ring of cells (1..nx-1) — both exactly the defects repaired in SIMPLE. - The "explicit" predictor read neighbours the same sweep had already overwritten, so the step depended on sweep order. - The pressure gradient was dropped entirely on the last interior face. Rewritten as a genuinely explicit predictor plus anchored-Neumann projection on the staggered grid, with the conventions SIMPLE now embodies: near-wall lines are unknowns with half-cell wall diffusion, continuity on every cell, boundary faces are prescribed data. Momentum-source and wall-velocity hooks added so the manufactured solution can reach it. Measured (16 -> 32 -> 64): L2 velocity 3.516214e-2, 1.953750e-2, 1.037512e-2 — orders 0.85 and 0.91, first-order upwind's rate — with max |div u| ~ 1e-9 in every cell. The errors agree with SIMPLE's on the same meshes to six or seven significant figures: an implicit under-relaxed outer iteration and an explicit time-marching projection land on the same discrete steady solution, which is what sharing a spatial discretisation must produce and is very hard for two independently wrong solvers to fake. 285 tests, 0 failing. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 19:28:39 -07:00
Omar SobhandClaude Fable 5	796cf173e6	rtx-cfd: second-order convection by deferred-correction TVD; MMS order 1.84, cavity closes on Ghia ... First-order upwind's O(h) numerical viscosity was the measured limit on the whole discretisation: MMS order ~0.9 at Re = 20 against 2.05 in the Stokes limit. This adds a ConvectionScheme parameter to SimPLE — Upwind (default, behaviour unchanged), TvdVanAlbada, TvdVanLeer — implemented by deferred correction: the upwind operator stays implicit, so a_p = sum(a_nb) and diagonal dominance survive unconditionally, and the limited high-order-minus-upwind flux difference enters the source explicitly at the current iterate. At a fixed point the two agree, so the converged answer is the TVD discretisation. Faces whose far-upwind node lies outside the domain fall back to pure upwind; wall faces pass no mass, so no correction enters. Measured by the manufactured solution (van Albada, 16 -> 32 -> 64): L2 velocity 1.325e-3 4.406e-4 1.232e-4 orders 1.59, 1.84 (upwind) 3.516e-2 1.954e-2 1.038e-2 orders 0.85, 0.91 The error is 27x to 84x below upwind's at equal resolution, the order climbs toward 2 (the shortfall is limiter clipping plus the boundary fallback, both of which shrink with h), the pressure error falls at the same rate, and continuity still holds to solver tolerance in every cell. On the Re = 100 lid-driven cavity at 65^2 the centreline minimum moves from -0.1932 (upwind) to -0.2036 against Ghia's -0.2109 — 59% of the remaining gap closed at equal resolution, converged in 790 iterations — and the vortex position moves from 0.5000 to 0.4844 toward Ghia's 0.4531. Both new cavity bounds exclude the upwind values, so falling back to first order fails them. 284 tests, 0 failing. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 19:16:48 -07:00
Omar SobhandClaude Fable 5	87cf392556	rtx-fea: re-enable the remaining CPU test modules; fix three real defects they caught ... All 33 remaining #[cfg(disabled)] test modules outside the GPU cluster are now enabled: assembly (dof_mapping, constraints, global assembly), boundary (mod + dirichlet/neumann/robin/thermal/contact), analysis (mod + static), materials (mod, linear_elastic, hyperelastic, plasticity), elements (mod, element_matrices, isoparametric, jacobian, quadrature), mesh (element_types, connectivity, topology, topology_repair), solvers (mod, direct, iterative, nonlinear) and lib.rs. Lib tests 117 -> 335, stable across repeated runs. Only gpu_solver_tests and the GpuMeshData fixture stay disabled — they need CUDA hardware and belong to the GPU tranche. Three real defects found by the newly-compiling tests, each fixed: - Direct solvers reused factorizations keyed on matrix SIZE alone. In a Newton loop the Jacobian changes every iteration but never its dimension, so LuDirect/CholeskyDirect/LdltDirect silently solved with the first iteration's factorization forever — Newton on x^2-4 crawled to x=1.955 in 1000 iterations instead of converging in 5. Invisible in single-solve linear analysis, which is why every green test passed over it. solve() now factorizes the matrix it is given. - AdaptiveQuadrature's refinement re-integrated the WHOLE domain once per subdomain, so each level multiplied the estimate by the subdomain count: integrating e^x over [-1,1] at tolerance 1e-10 returned ~75 instead of 2.35. The recursion now descends into each sub-box with its share of the error budget. - compute_skewness read Jacobian columns as coordinate-line tangents, but the trait's jacobian() stores tangents in ROWS: on a sheared parallelogram whose tangents meet at 14 degrees it reported skewness 0.43 instead of 0.84 — measuring per-component gradients, not mesh skew. Fixtures corrected rather than the code where the fixture was wrong: sigma_yy ~ 0 asserted uniaxial-stress physics on a uniaxial-strain state (exact Lame values now asserted); an "unstable" orthotropic parameter set that satisfies the determinant stability condition (delta = 0.187 > 0); a unit-cube hex Jacobian of 1.0 that assumed a unit reference element (it is 0.125 from [-1,1]^3); a "distorted" quad whose centre Jacobian is exactly orthogonal, asserted as skewed (flattening and shearing now tested separately); a quality score below the implementation's own calibration; Rayleigh damping fed the scalar-field mass (now expanded via the Kronecker identity, with C = alpha*M + beta*K asserted entry-wise); an element factory required to construct Point/Line types that have no implementation; and DOF counts that encoded the repaired 3-DOFs-per-node-on-2-D defect. MaterialDatabase::add_material call sites updated to the (id, material, name) signature; ConnectivityInfo::build takes elements only; TopologyRepair::triangle_quality (normalized 4*sqrt(3)*A/sum(a^2)) added for the repair tests; create_subdomain_rule_* widened to pub(super) for the quadrature tests. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 18:52:50 -07:00
Omar SobhandClaude Fable 5	8495a690d9	rtx-fea: build the missing mesh-generation APIs and re-enable 8 test modules ... The largest cluster of the 128 compile errors behind the disabled test modules was one missing API family. Now built, each with invariant tests a plausible-wrong mesh fails: - Rectangle::generate_quad_mesh / generate_tri_mesh — structured grids, CCW elements, exact area sums asserted - Circle::generate_tri_mesh — centre fan plus ring bands; tiles the inscribed polygon exactly - Box3D::generate_hex_mesh / generate_tet_mesh — the tet split is the Kuhn/Freudenthal 6-tet subdivision, conforming across cells, positive volumes summing exactly to the box - Sphere::generate_tet_mesh — concentric UV shells, centre fan, prisms split by the Dompierre smallest-index diagonal rule so neighbouring prisms agree; conformity and closed-boundary asserted via face counting - Mesh::validate — empty/inconsistent/orphan checks plus signed-area orientation for planar Tri3/Quad4, which is what an inverted connectivity fails - Mesh::find_boundary_edges / find_boundary_faces / calculate_edge_normal, Node::distance_to / with_label Re-enabling the tests found a real defect: geometry::Face derived order-sensitive PartialEq/Hash, so the same face listed by two adjacent elements (different start node, opposite winding) never compared equal. A 2x2x2 hex mesh reported 32 boundary faces instead of 24 — and find_boundary_nodes in 3-D and the 3-D surface-area statistic sit on the same counting. Face identity is now canonical (sorted ids; quads keep their diagonal pairing). Partitioning: the fixtures targeted an instance API that never existed — MeshPartitioner::partition is an associated function. Two real gaps fixed: interface_elements was never populated, and requesting more partitions than elements produced useless empty partitions (now clamps). Fixtures corrected rather than the code where they encoded abandoned designs: global DOF numbers on nodes (DofMap's job), element thickness/property bags nothing reads, a 0-to-1 quality score that never existed, and a clockwise sliver that validate now rightly rejects. The GPU data conversion test stays disabled with the GPU solver tranche. Lib tests 72 -> 117, stable across 5 runs, all integration suites green. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-19 18:29:55 -07:00
Omar SobhandClaude Opus 5	1a740e0b2c	rtx-cfd: the wall treatment is second order, not first — correct the record ... The manufactured-solution test carried a hypothesis for why the observed order sits below 1: that `(u_P - u_wall)/(dy/2)` approximates the wall gradient at y = dy/4 rather than at the wall, making the near-wall rows first order. Measuring in the Stokes limit refutes it. With convection negligible every remaining operator is second order, so the observed rate there reports the wall treatment directly: rho = 1.000 (Re = 20.00) 3.52e-2 1.95e-2 1.04e-2 orders 0.85 0.91 rho = 0.001 (Re = 0.02) 2.21e-3 5.35e-4 1.28e-4 orders 2.05 2.06 2.05 and 2.06. The half-cell wall term is second-order accurate and the Stokes discretisation reaches its nominal rate. The shortfall at Re = 20 is first-order upwind and nothing else, which is what a first-order convection scheme is supposed to give. Comment corrected rather than left standing: a plausible explanation that happens to be wrong is worse than none, because it sends the next person to fix something that is not broken. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>	2026-08-19 17:42:14 -07:00
Omar SobhandClaude Opus 5	698c844926	solvers: near-wall momentum, Newmark dynamics, QM6, and MMS across elements ... Four parallel work items plus two defects found while integrating them. 561 -> 592 tests, 0 failing, verified stable over repeated runs. ## rtx-cfd: solve the near-wall velocity lines Every u row sits at y = (j+0.5) dy and every v column at x = (i+0.5) dx -- strictly interior. The sweeps froze rows 0 and ny-1 and columns 0 and nx-1 and treated whatever was stored there as a boundary condition, which imposed wall values half a cell inside the domain. They are now unknowns, with the wall entering through the control volume's half-cell conductance (mu dx / (dy/2)), zero convective flux through the wall, and the wall's tangential velocity in the source. That in turn makes continuity enforceable on every cell, with a neighbour coefficient zero only for a genuine boundary face. Extending continuity had been tried before and broke convergence; it works now because the near-wall lines are no longer frozen. Order matters here. Manufactured solutions, which is how any of this is known: n L2 velocity order max |p - p_exact| 16 3.516212e-2 - 9.245576e-2 32 1.953751e-2 0.85 5.225739e-2 64 1.037523e-2 0.91 2.796415e-2 Velocity error is 7.4x smaller at n=16, and the observed order rises from 0.48 toward 1. The pressure error was 0.408 -> 0.624 -> 0.756, *growing* with refinement; it now falls. Divergence on the outer ring of cells goes from 1.0e1 to 2.5e-10. A separate defect found on the way: u_source_term was computed and never called, so the x-momentum equation carried no body force at all while the y-momentum one did. That is exactly the u-versus-v asymmetry the earlier diagnosis had flagged as an unexplained clue. Cavity at 65^2, against Ghia's u_min = -0.2109 at y = 0.4531: -0.1792 at 0.3906 before, -0.1932 at 0.5000 after, in 733 iterations rather than 971. The cavity test now sets FreeSlipWall on all four sides plus the lid through the new set_wall_velocity hook. That is not a weakened benchmark: on a staggered grid the only velocity component living *on* a boundary is the normal one, which is what FreeSlipWall prescribes, and the tangential no-slip arrives through the half-cell wall term with wall velocity zero on the three stationary walls. Prescribing whole u rows and v columns, as before, pins lines half a cell inside the domain and over-determines the cells beside them once every cell has a continuity equation. ## rtx-fea: DynamicAnalysis, previously a stub returning zeros Newmark-beta in acceleration form -- the displacement form divides by beta dt^2, singular at beta = 0 -- with Rayleigh damping, the effective matrix Cholesky-factorised once and reused. Initial acceleration is solved from M a0 = F0 - C v0 - K u0 rather than assumed zero, which would destroy the second-order rate. Verified two ways that cannot both be faked: against the closed-form single-degree-of-freedom response, undamped and damped, with the measured order of accuracy; and against the free-vibration period of the same bar whose modal frequencies are already validated. Time domain and frequency domain come from different code paths. ## rtx-fea: QM6 incompatible modes Wilson's Q6 with Taylor's correction, added alongside compute_stiffness_ matrix rather than replacing it -- the existing method is byte-identical, which matters because the manufactured-solution verification depends on it. Internal modes statically condensed; the incompatible strain block evaluated at the element centre, which is what makes the patch test pass on distorted elements. ## rtx-fea: manufactured solutions across the element library Quad4 order 2.00 Tri3 order 1.98 Quad8 order 3.00 Hex8 order 1.96 (new 3-D solution) Each element asserts its own theoretical rate. ## Two defects found while integrating Reverse Cuthill-McKee node ordering was nondeterministic. All three of its orderings -- seed selection, neighbour ordering, and the trailing sweep -- were decided by HashMap/HashSet iteration order, which std randomises per process. On a rectangular mesh every corner ties at minimum degree, so two calls to displacement_only on the same mesh in the same process returned different DOF indices for the same node, agreeing in only 5 of 20 measured runs. Ties now break by node id. This surfaced as a coin-flip test failure -- 12 in 25 runs -- and would have been dismissed as flaky rather than diagnosed had the integration pass not re-run it. Quadrature: triangle(3) weights summed to 0.25 against a reference area of 0.5, and tetrahedron(3) to 1/36 against a volume of 1/6. Both divided weights that were already tabulated for the reference measure by that measure again, so both rules integrated everything to a fraction of its value -- invisibly, since a scaled quadrature leaves the stiffness matrix symmetric, the mass matrix positive definite and the rigid-body modes exact. New test asserts every rule integrates 1 to its reference measure, across every family and order, plus Gauss-Legendre exactness to degree 2n-1. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>	2026-08-19 15:39:20 -07:00
Omar SobhandClaude Opus 5	b5814a304f	rtx-cfd: manufactured solution finds the diffusion conductances were 1/h too ... large Applies MMS to the SIMPLE solver. It found a major discretisation error on the first run, which is the point of the method. The diffusion conductances read `mu / dx` and `mu / dy`. Finite volume requires `Gamma * A / delta` — the face area over the distance between the nodes it separates — so they should be `mu * dy / dx` and `mu * dx / dy`. The face area was missing entirely, making viscosity too large by a factor of `1/h`: sixty-five times on a 65x65 mesh. Every other term in the equation was already a force (`dp * dy` for pressure, `rho u dy` for the convective flux), so the mismatch was confined to diffusion. The consequence was that the solver ran at an effective Reynolds number far below the one requested. Before the fix the manufactured-solution error did not reduce under refinement at all — observed order about -0.05, because the spurious viscosity grows with the mesh. After it, the error falls monotonically. This also explains an apparent regression that is really a correction. The cavity vortex position moved from y = 0.484 to y = 0.391 against Ghia's 0.4531, which reads as worse agreement. It is not: a strongly over-diffusive cavity approaches Stokes flow, whose vortex sits near mid-height, so the old number was closer to the reference than the scheme deserved. Correcting the viscosity exposed the discretisation's own error. The test now states that disagreement plainly rather than asserting a band around the reference. What MMS reports now, and it is not yet good enough: n = 16 L2 velocity error = 2.586104e-1 order - n = 32 L2 velocity error = 1.797373e-1 order 0.52 n = 64 L2 velocity error = 1.277188e-1 order 0.49 First-order upwind should give 1. It gives about 0.5, and the u component is markedly further from exact than v on the same mesh. Both say there is at least one more defect in the discretisation or its boundary treatment, and the asymmetry between the two momentum equations is the clue. The test asserts only monotone error reduction — what is established — and records the shortfall, because asserting a rate the solver does not achieve would either redden the suite or invite someone to weaken it later. This changes the plan: raising the observed order to 1 is now a precondition for the second-order convection work rather than a consequence of it. There is no value in adding a higher-order scheme to a discretisation that has not demonstrated first order. Supporting changes: - `SimpleSolver::set_momentum_source` applies a volumetric body force, which is what lets a manufactured solution be imposed at all. - Divergence is now detected by growth, not only by NaN. The 8x8 case at Reynolds 10^6 reached 1e149 before anything caught it, because `is_finite` stays true right up until it does not. - `test_simple_solver_workflow` specified water properties on a unit domain, which is Reynolds 10^6 on ten cells: no steady laminar solution exists and the solver diverges on it, correctly. It passed only while the excess diffusion stabilised it. Now set to Reynolds 100. 561 tests across the three crates, 0 failing. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>	2026-08-19 12:25:52 -07:00
Omar SobhandClaude Opus 5	10e5f9cb90	rtx-cfd: fix the cell-centre velocity interpolation, which was half a cell out ... `get_velocity_at` averaged u-faces `i - 1` and `i` to report the velocity at cell `i`. On this staggered layout `u` is `(ny, nx + 1)` and cell `i` is bounded by faces `i` and `i + 1` -- which is the convention `compute_mass_source` uses to form the divergence, and therefore the one that defines the grid. The two disagreed by one index. Consequences: every profile read through this function was shifted half a cell west of the field the solver actually computed, the first and last cells were special-cased to a single face, and the outermost face was never read at all. It is a diagnostic path rather than a solve path -- the residuals are byte-identical before and after -- but the cavity comparison against Ghia is taken through it, so the reported vortex position was affected. The corrected grid study, unchanged in the solve: n u_min y 17^2 -0.1257 0.4375 33^2 -0.1550 0.4688 65^2 -0.1743 0.4844 97^2 -0.1825 0.5000 Ghia -0.2109 0.4531 The shift matters most where the grid is coarse and washes out under refinement, which is what a half-cell offset should do. Found while establishing where each staggered variable physically sits, a prerequisite for applying the method of manufactured solutions to this solver. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>	2026-08-19 12:10:41 -07:00