jgrusewski d54b49efc1 fix(dqn): C51 bias breakout — adaptive eps_dir floor from trade-rate undershoot
Prior C51 bias fix (commit 7a3d88646: ISV-adaptive Boltzmann tau floor)
had no measurable effect on the post-training Hold/Flat collapse —
empirically confirmed in train-bscl2 epoch 2: val_dir_dist
[short=0.135 hold=0.358 long=0.142 flat=0.364], identical to the
pre-fix run [short=0.136 hold=0.348 long=0.148 flat=0.367].

Root cause: once Q-values reflect tx_cost-driven aversion, Boltzmann
correctly samples the biased Q distribution regardless of tau. Tau
adjustments protect cold-start exploration but can't combat learned
preferences. The 2% static eps_dir floor allows only 0.5% random
sampling per direction — too little to break the Q-value lock-in or
generate enough Long/Short experiences for edge discovery.

Fix:
  if (ISV available) {
    passive_pressure = clamp(0, 1, 1 − ISV[71]/max(ISV[72], 1e-4))
    eps_dir = max(eps_dir, 0.5 × passive_pressure)
  }

ISV[71] = TRADE_ATTEMPT_RATE_EMA (current Flat→Positioned rate, B.2 producer)
ISV[72] = TRADE_TARGET_RATE (target frozen at epoch 5 from measured EMA)

Feedback semantics:
- attempt_rate >= target → passive_pressure=0 → eps_dir at baseline 0.02
- attempt_rate = 0 (fully passive) → passive_pressure=1 → eps_dir floor=0.5
- intermediate → linear blend

The 0.5 ceiling is a structural blend point (half random / half policy)
— maximum exploration that still preserves directional Q-signal
propagation through the replay buffer. Not a tuned magnitude.

Cold-start safety: ISV[72] is 0 until epoch 5 freeze; with the 1e-4
target floor, passive_pressure clamps to ≈1 immediately, but eps_dir
also has a baseline 0.02 EPS_FLOOR so the formula's max() picks
whichever is larger. Once ISV[72] freezes, the feedback loop activates
properly.

Eval mode unaffected (eps logic gated behind !eval_mode).

Direction branch only — magnitude/order/urgency don't have the
Flat-attractor problem.

ISV-driven, no new ISV slots, no tuned constants per
feedback_isv_for_adaptive_bounds.md and feedback_adaptive_not_tuned.md.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-26 22:51:34 +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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