jgrusewski cdfaa5e7da fix(rl): mean_abs_pnl_ema tracks all non-zero rewards, not just closes
Cluster smoke `alpha-rl-9cbpj` diag.jsonl revealed that 64% of
non-zero reward events (170 of 266 across 1000 steps) occur on
non-done steps — mid-trade PnL deltas from trail-stop adjustments,
mark-to-market, or partial fills. The reward_scale controller's
mean_abs_pnl_ema was done-gated, so these mid-trade reward
magnitudes never contributed to the scale calibration.

Concretely: closed-trade |PnL| settled around $832-910, controller
calibrated `scale = 1/910 ≈ 0.0011`. Mid-trade swings can reach
$2,390 (step 590 raw reward); scaled by 0.0011 they produce
reward = -$58.8, which V regression must learn to predict. With
the C51 V-head atom support of [−1, +1] the −58.8 target generates
MSE ≈ 3,456 (canonical incident, prior smoke). The controller is
calibrated for the wrong distribution.

## Fix

The `ema_update_on_done` kernel's "dones" parameter is really a
generic gate tested as `d >= 0.5f`. Passing `reward_abs_d` as the
gate (instead of `dones_d`) gives "gate on |reward| ≥ 0.5" which
for any practical dollar magnitude means "gate on non-zero reward
event". Zero-reward steps still stay excluded so the EMA isn't
biased toward zero on idle hold steps.

One-line change at the launch site (the `obs` and gate arguments
become the same buffer, `reward_abs_d`). No kernel modification
needed — the same kernel serves both done-gated EMAs (e.g.
`mean_trade_duration`) and reward-event-gated EMAs (this one)
just by choice of which buffer is passed as the gate.

## Expected effect on next smoke

The new mean_abs_pnl_ema will track the average |reward| across
both close events ($832-910) and mid-trade events ($100-2400).
With mid-trade magnitudes typically 2-3× larger than close
magnitudes, the new mean will be higher → reward_scale lower →
all reward magnitudes (close AND mid-trade) get squeezed into
the V-head's atom support more consistently.

The step-590 spike (l_v=3,456) should drop to O(1).

## Verified gates (local sm_86)

All R-phase tests still green — the change is a single-argument
swap at the launch site, no kernel logic touched. Tests pass
unchanged because they don't exercise the mid-trade reward path
(test harness uses synthetic LobSim with simple cross-and-close
mechanics, not the trail-stop / partial-fill mid-trade dynamics
that surfaced in the cluster smoke).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-23 16:55:41 +02:00

Foxhunt

Production HFT trading system in Rust.

Architecture

The workspace contains 32 crates organized as follows:

Core Libraries (16)

Crate Purpose
trading_engine Order processing, FIX 4.4, IB TWS, SIMD, RDTSC timing
risk VaR, Kelly, circuit breakers, kill switches, compliance
risk-data Risk data types and shared structures
trading-data Trading data types
ml DQN Rainbow, PPO, TFT, Mamba2, ensemble inference
ml-data ML data types and feature definitions
data Market data ingestion and storage
backtesting Replay engine, strategy tester
adaptive-strategy Ensemble execution, microstructure analysis
common Shared types, resilience, error handling
storage S3 and local model storage
model_loader Model serialization and loading
market-data Market data feed handlers
database PostgreSQL access layer (SQLx)
config Configuration management
tli CLI commands and tooling

Services (8)

Service Purpose
backtesting_service gRPC backtesting service
broker_gateway_service FIX routing, broker connectivity
trading_service Core trading operations
ml_training_service Model training orchestration
data_acquisition_service Market data acquisition
trading_agent_service Autonomous trading agents
api_gateway gRPC API gateway with auth
web-gateway Axum REST + WebSocket gateway

Frontend

web-dashboard/ -- React 19 + TypeScript + Vite + TradingView charts.

Building

# Check compilation (no PostgreSQL required)
SQLX_OFFLINE=true cargo check --workspace

# Run tests for a specific crate
SQLX_OFFLINE=true cargo test -p <crate> --lib

# Clippy
SQLX_OFFLINE=true cargo clippy --workspace

ML Models

Four production model architectures on Candle v0.9.1 with CUDA:

  • DQN Rainbow -- Deep Q-Network with prioritized replay, dueling heads, noisy nets
  • PPO -- Proximal Policy Optimization with GAE and LSTM policies
  • TFT -- Temporal Fusion Transformer for multi-horizon forecasting
  • Mamba2 -- State space model for sequence prediction

Each model has a standalone trainer and a UnifiedTrainable adapter for the hyperopt pipeline.

Infrastructure

  • Git: Gitea at git.fxhnt.ai (Tailscale-only), Scaleway DEV1-S
  • Observability: OpenTelemetry OTLP (env OTEL_EXPORTER_OTLP_ENDPOINT)
  • Database: PostgreSQL with SQLx offline mode for CI

License

Proprietary. All rights reserved.

Description
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