494125c104
Designs the structural fix for the C51 expected-Q Hold/Flat bias exposed
by the Kelly val-Flat-collapse fix. The bias is a manifestation of a
deeper project-wide pearl:
"Distributional RL aggregation discards uncertainty;
action selection must restore it."
Any value head representing Q as a distribution (atoms, quantiles,
ensembles) MUST expose both E[Q] and σ(Q) to action selection. Boltzmann
on E[Q] alone produces structural bias toward low-variance actions
regardless of expected payoff — the C51+IQN Flat-attractor is one
instance of this lost-information pattern.
Fix: extract σ(Q) from BOTH C51 atoms (closed form) and IQN quantiles
(IQR/1.349), blend by loss-time weight, feed Q_eff = E[Q] + κ·σ
(κ=1.0 structural identity) to direction-branch Boltzmann ONLY.
4-phase implementation:
Phase 0 — TDD hypothesis verification (Rust mirror functions + 5 unit
tests including GPU integration on real checkpoint)
Phase 1 — Audit existing reward levers (B.2, CF, PopArt, Q-target)
via 6 unit tests; fix any bugs found
Phase 2 — UCB integration: new compute_q_with_uncertainty kernel,
modified action_select, Rust orchestration, project-wide
aggregation contract in dqn-wire-up-audit.md
Phase 3 — Verification per Plan 5 Task 5 multi-seed × multi-fold
5-layer verification gate; 8 risks with mitigations; 4 stop conditions
that halt execution and force redesign.
Existing band-aid fixes (Kelly cap, eps-floor, tau-floor) stay — they
address symptoms at different layers. UCB adds the missing aggregation
step that was the common root across all the symptoms.
Direction-branch only — magnitude/order/urgency don't have the
Flat-attractor (atom-mass collapse asymmetry).
5-7 days active work across 4 sub-plans; each gets its own
writing-plans cycle.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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.