feat(aux-labels): replace D with A+B paired labels + loader/trainer migration (CB1+CB2)
Smoke 1 v2 empirically falsified the D-style labels: 99.99% of K=100 D-labels
were negative on real ES MBP-10 (cost+1.5×MaxDD dominates every typical
100-tick move). Aux head couldn't escape predicting the mean.
CB1 — replace label generator:
- generate_outcome_labels_d → generate_outcome_labels_ab returning
OutcomeLabelsAB { y_prof_{long,short}, y_size_{long,short}, sigma_k,
cost_price_units, pos_fraction }
- y_prof = 1 iff signed_pnl > 2×cost (binary, class-weighted BCE target)
- y_size = signed_pnl / σ_K (σ-normalized regression target,
conditional-masked when y_prof=0)
- σ_K: rolling 1000-bar Welford std of K-step log-returns, floored at
cost/4 per pearl_trade_level_vol_for_stop_distance
- pos_fraction: per-(direction, horizon) positive class fraction for
downstream BCE pos_weight balancing
- 10 unit tests validating sign-correctness, NaN edges, balance,
cost-threshold, sigma-floor, per-horizon independence, error paths
CB2 — atomic caller migration:
- LabeledSequence + LoadedFile: outcome_long/short (2 arrays) → 5 arrays
(prof_long, prof_short, size_long, size_short, sigma_k) + pos_fraction
- Loader splits new generator's outputs + propagates pos_fraction
file-level into each yielded LabeledSequence
- step / step_batched signatures widened to 7 params + pos_fraction
- alpha_train.rs: 4 separate batches + per-snapshot row build for each
- last_pos_fraction stashed on PerceptionTrainer
- aux test fixture (synthetic_aux_outcomes) updated to emit 4 arrays +
pos_fraction matching the constant-up-ramp test signal
- HOLDING PATTERN: step_batched body validates new arrays + stages
prof-binary through the existing D-era Huber kernel so training
produces a real gradient. CB3 rewrites the kernel; CB4 widens head
outputs; CB5 wires BCE+Huber proper loss with class weighting.
cargo check --workspace --all-targets: clean (only pre-existing cudarc
cupti + ml insert_batch unrelated errors).
cargo test -p ml-alpha --lib: 43 passed (15 multi_horizon_labels).
cargo test -p ml-backtesting --lib: 33 passed.
stacked_trainer_aux_supervision RTX 3050: pass (huber=0.0004, dir_acc=1.0,
stop_grad lifted).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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