The BITBRAIN name was sitting on a gun with no network in it. This is the gun
that actually runs the algorithm: an ADE layer (thresholded random projections
with ONLINE threshold adaptation) feeding the SBC head from
common_libs/bitbrain/, with the counted+decay mode available.
common_libs/guns/bitbrain_net.nim the gun
rack name BITBRAIN, rack id 17 (rack 17 -> 18 guns), both new guns default OFF
admitted by TR_RACK_BITBRAIN=both AND TR_BITBRAIN_NET=1 (the switch that also
disowns LEADGAIN's legacy TR_BITBRAIN_* aliases)
OUTPUT: a fine-grained aim CORRECTION on top of Pattern - the probability-
weighted mean of the nClasses class centres under inferProb - not a direct aim
point from the argmax. That is the shape docs/bitbrain_gate.md measured, and
Pattern is already a strong predictor, so the net's job is the signed residual.
Below TR_BITBRAIN_MINOBS the shift is exactly 0 and Pattern is returned
unchanged.
INPUT: a CONFIGURED set of FEATURE BLOCKS (TR_BITBRAIN_FEATURES=name:W), each
block's width == its resolution, laid out as a thermometer code over 0/255 slots
(so an ADE synapse 'matches' when its polarity agrees with the slot and a random
ADE fires iff its w synapses all match, rate 2^-w). Default is 52 slots over 9
blocks. NO long temporal window, per docs/state_window_gate.md: the only history
is a 12-tick ring feeding three rate/turn quantities.
Every knob env-configurable: _INPUT (width), _NCLASSES, _NADES, _WIDTHS
(clause widths), _FEATURES, _SPAN, _MODE, _DECAY_EVERY, _DECAY_SHIFT,
_MINOBS, _ADAPT_EVERY, _TARGET, _NETSEED, _NETLOG, _NET_RESET_ON_TARGET.
MEASURED SCALING (measure_bitbrain_scaling.nim, 3 recorded runs, 37412 ticks,
-d:release, one predict per power bin per tick, timed region = predicts only):
RAM 1.59 MB default (98.6% SBC tensors); linear in nClasses, QUADRATIC in
nAde, FLAT in input width; counted/bitset = 7.30x on RAM, ~1x on time.
ms/tick 2.70 default = 21% of the 13.16 ms budget; 64 classes busts it (149%),
nAde 512 uses 74%, nAde 64 uses 2%.
CAPACITY vs ACCURACY: over a 100x RAM range the offline mean |err| moves
17.254 -> 17.115 deg around Pattern's 16.964, and the sign flips along the
nClasses axis, so it is noise, not a trend. The corrector is consistently
slightly WORSE than Pattern. The ceiling is the STATE, not the classifier.
VETO-CAPABLE OFFLINE CHECK ONLY (docs/offline_harness_trust.md), never
presented as a live win.
ENGAGEMENT is proven, not assumed: test_bitbrain_net.nim (42 checks) shows 0
bytes before first use, different inputs -> different class outputs, a learn
raises SBC occupancy, bitset learn idempotent while counted learn is monotone,
threshold adaptation runs, and the global RNG is untouched.
Parity: shipped rack still onlyPattern, shipped movement still strafe. Guards:
test_env_report 25, test_rack_membership 48, test_tm_pattern_registration 20,
test_lead_gain_registration 13, test_lead_gain_legacy 24, test_bitbrain 56,
test_gun_harness 39, test_tfil_commit_env 30, test_bitbrain_net 42.
Clean archive build: [SuccessX].
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The gun at rack id 16 learned a multiplier for Pattern's lead, separately
per range band. It was called BITBRAIN and shipped a TR_BITBRAIN_* prefix,
which is why the name read as a neural network it no longer contains.
guns/bitbrain_gun.nim -> guns/lead_gain.nim (rack id 16 UNCHANGED)
RackGunNames[16] BITBRAIN -> LEADGAIN
TR_BITBRAIN_* knobs -> TR_LEADGAIN_*
[bb] log line -> [lg]
BACKWARD COMPATIBILITY is mandatory: the live .env carries
TR_RACK_BITBRAIN=both, TR_BITBRAIN_GAINS, TR_BITBRAIN_MEM=decay and
TR_BITBRAIN_LOG=1, and those must keep behaving identically. The new ADE+SBC
gun (next commit) claims the BITBRAIN name and the TR_BITBRAIN_* prefix, so
the namespace is disambiguated by ONE deterministic switch, TR_BITBRAIN_NET
(default 0):
TR_BITBRAIN_NET unset/0 -> LEGACY: the 14 frozen legacy suffixes are aliases
for TR_LEADGAIN_*, and TR_RACK_BITBRAIN still
selects rack id 16. One [depr] line on stderr
names the new spelling of each honoured knob.
TR_BITBRAIN_NET = 1 -> the TR_BITBRAIN_* names belong to the new gun.
The legacy suffix set and the new gun's knob set are DISJOINT, so no name is
ever claimed twice; the new name always wins over its alias.
Parity: shipped rack is still onlyPattern, shipped movement is still strafe.
Guards unchanged: test_env_report 25, test_rack_membership 48,
test_tm_pattern_registration 20, test_lead_gain_registration 13 (was
test_bitbrain_registration), test_bitbrain 56, test_gun_harness 39,
test_tfil_commit_env 30. New: test_lead_gain_legacy 24.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Task A — the gain region Phase 0 never covered (gain < 1). Extend the
prediction-quality ruler with gain 0.25/0.50/0.75 arms and a fixed causal
per-band arm. Full 70-run result: the hitProxy-argmax curve is
[1.00, 1.00, 1.00, 0.00, 0.00] — Pattern below 300 px, HeadOn above —
worth +0.13 pp at 300-450 and +2.16 pp at 450+ (0.0767 -> 0.0984). Lead
correlation is identical for every g>0 (Pearson is scale-invariant), so a
shrinking gain adds no lead information; and the least-squares optimum
[1,1,1,1,0.25,0.25] diverges from the hitProxy optimum because Pattern's
lead errors are bimodal.
Task B — rebuild guns/bitbrain_gun.nim as a lead-gain corrector:
aim = LOS + gain*(patternAim - LOS), gain learned online per range band by
ranking candidate gains on the hit-probability proxy (the observed lead
label via tmhObservedAt), gated to range >= 300 px. ADE+SBC output removed.
Offline (70 runs): Pattern below 300 px, +0.37 pp at 300-450, +1.90 pp at
450+ (hitProxy 0.0957 vs 0.0767), matching the fixed rule to within 0.27 pp
at 450+ and exceeding it at 300-450. ~0.0007 ms/tick marginal (old gun
~0.114 ms/tick). Default off; rack membership, env report and guard tests
(bitbrain 32, registration 13, rack 48, tm_pattern 20, env_report) unchanged
and green.
Ledger: docs/bitbrain_campaign.md Phase 1, including the three on-file
negatives and the causal-shippability note. No live claim.
New harness (common_libs/gun_harness/prediction_quality.nim +
common_libs/tests/run_prediction_quality.nim): per-gun single-tick aim error in
degrees against the true continuous interception point on the recorded
live-vs-real-DrussGT corpus (/tmp/tfil_ab2/out, 70 runs, 899607 ticks), per
range band, with the hit-probability proxy mean(|err|<=atan(18/range)).
Validated: recorded hits separate from misses 13.34x px (reference 11.59x),
perfect-oracle max |err| = 0, correct ordering on synthetic ground truth, two
full runs byte-identical. Fixed a wrap180 bug (Nim float mod keeps the dividend
sign) that inflated the negative error tail.
Bar (mean|err| deg [hitProxy] at 450+): Pattern 16.19 [0.077], naive-linear
22.86 [0.054], TMHorizon 16.20 [0.076], BitBrain 16.20 [0.077], static HeadOn
12.33 [0.098], oracle 0 [1.0]. Lead-gain sweep on Pattern is a dead end (1.0
wins every band). Naive-linear applies ~1.8x Pattern's lead but carries no more
lead information (corr 0.178 vs 0.165) and is strictly worse. Ledger:
docs/bitbrain_campaign.md. All verdicts remain live-only.
SirStone