4 Commits

Include renames

Author	SHA1	Message	Date
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