Adds the two sweep axes that the spec's deployability grid needs but
were missing from the kernels:
Threshold gate (decision_policy.cu, both kernels):
- New per-backtest `threshold_per_b` array kernel arg.
- Pre-Kelly prelude: if max_h |alpha[h] - 0.5| * 2 < threshold[b],
emit noop and return. Kept deterministic from alpha alone so the
threshold pre-registration step (p60-p95 absolute calibration on a
validation window, future P6) reflects exactly what gets gated in
deployment.
Per-fill cost integration (resting_orders.cu / apply_fill_to_pos):
- apply_fill_to_pos signature grows three args: b, cost_per_lot_per_side_per_b,
total_fees_per_b. Single insertion point at line 90.
- After the close-leg realized_pnl math runs (so the gross unwind P&L
is preserved), deduct fill_cost = filled_lots * cost_per_lot_per_side[b]
from pos.realized_pnl AND accumulate into total_fees_per_b[b].
- Net-of-cost semantics: isv_kelly_update_on_close reads realized_pnl
delta which is now net of cost — Kelly state learns from realistic
return distribution.
- All 3 apply_fill_to_pos call sites in step_resting_orders updated.
order_match.cu's submit_market_immediate path is dead code in the
post-P1 flow (everything routes through seed_inflight_limits_batched
→ step_resting_orders → apply_fill_to_pos) so not touched here.
BatchedSimConfig + UniformSimParams + BacktestHarnessConfig gain
threshold + cost_per_lot_per_side fields. All UniformSimParams
constructors in tests and main.rs updated with defaults (0.0, 0.0 =
gate disabled, frictionless).
Regression:
- threshold_gate_skips_low_conviction (p=0.51 + threshold=0.10 → noop)
- threshold_gate_allows_high_conviction (p=0.8 + threshold=0.10 → buy 1+)
- threshold_zero_is_passthrough (sanity)
- All P1+P2+P3 tests continue to pass via the new ABI.
cost_deducted_at_each_fill + kelly_state_sees_net_return end-to-end
tests deferred — they require a full submit_market → fill → close
sequence, which the production smoke exercises.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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