The audit inferred (from code) that GF/DecayGF/KNN pop the OLDEST wave on
resolution, while under bmPath bullets leave the arena in NON-FIFO order - so an
outcome could be attached to the wrong wave. It also noted that `starved=0` does
NOT rule this out. Both halves are now MEASURED.
MISPAIRING RATE (10 DrussGT fixtures, real VirtualTracker, 344k resolutions/gun):
gun bmPath mispair label err bmPoint mispair label err
GuessFactor 36.48% 19.39% 18.24% 7.62%
DecayGF 36.85% 19.52% 20.57% 8.64%
KNN 57.91% 27.63% 29.75% 11.58%
(starved = 0 everywhere, exactly as the audit predicted)
So ~1 in 5 GF/DecayGF learning samples and ~1 in 4 KNN samples carried a WRONG
guess-factor bin. This is a material corruption of the learning signal.
FIX: the same fireTick-keyed ring scheme `tsetlin.nim`/`tm_selector.nim` already
use - `slot = (fireTick*4 + bin) mod 1024` (period 256 ticks, longer than the
~91-tick max flight), looked up by exact key. Public interfaces unchanged; added
`waveResolved`/`waveMispaired` integrity counters. AFTER: mispaired = 0 and
starved = 0, both metrics, all three guns.
EFFECT ON HIT RATE: SMALL AND NOT SIGNIFICANT. bmPath 4000 samples/gun:
GuessFactor 23.20% -> 23.02% (-0.18pp, per-run sign-flip p=0.750)
DecayGF 23.80% -> 24.25% (+0.45pp, p=0.625)
KNN 18.27% -> 18.80% (+0.53pp, p=0.547)
bmPoint: +0.05 / +0.33 / -0.15pp, p = 1.00 / 0.50 / 0.50. Per-run ranges overlap
almost completely. A bullet-level z-test is anti-conservative (bullets within a
fixture share a trajectory) and its KNN p=1.9e-16 cannot be trusted given ~10
effective independent runs.
PLAIN READING: this is a CORRECTNESS fix, not a measurable hit-rate win. It
removes a 36-58% mislabelling of the learning signal; the point estimates move by
at most ~0.5pp, within run-to-run noise. Stated plainly rather than oversold.
A REGRESSION IT CAUGHT IN ITSELF (and this explains the SIGSEGV another job saw
and correctly attributed to a concurrent knn_gun.nim rewrite): the first
implementation put an inline `array[1024, KNNWave]` (~100KB) inside each gun,
which overflowed the default 8MB stack and made `test_power_selection` SIGSEGV.
Causation was proven by stashing only the three gun files (test passed), then
fixed by making the rings heap-backed `seq`. Verified: `test_power_selection`
3 PASS on the default stack, and zero inline `array[1024]` remain.
Guards: test_wave_pairing 17 (new, pure), test_gun_harness 39,
test_vbullet_metric 11, test_power_selection 3, test_adaptive_radar 41,
test_tfil_ring_weights 24, test_power_policy 26, test_ram_decision 28.
ModularBot compiles. Adds audit_wave_pairing.nim and compare_pairing.nim.
