jgrusewski e412f12e33 fix(ml): restore exploration mechanisms for DQN action diversity
The C2 fix from the previous session was too aggressive — it eliminated
ALL exploration mechanisms simultaneously:

1. epsilon forced to 0.0 when noisy nets active (select_action)
2. count bonus removed from Q-value computation (metrics only)
3. noisy_epsilon_floor config field declared but never read

This left noisy nets as the sole exploration mechanism, which produces
perturbations too small to overcome Q-value gaps (A4=0.12 vs others≈0.02).
Result: 20/20 hyperopt trials hit fallback objective with 1/5 diversity.

Fixes:
- select_action: use noisy_epsilon_floor (not 0.0) as effective_epsilon
  when noisy nets active — guarantees minimum random action rate
- select_action: re-enable UCB count bonus on Q-values before argmax
  (both IQN and standard paths) for directed exploration
- select_action_with_confidence: same fixes for consistency
- trainer: set epsilon to noisy_epsilon_floor (not 0.0) at init
- hyperopt: widen noisy_epsilon_floor range from [0.0, 0.05] to
  [0.03, 0.15] with default 0.05

Exploration now has two complementary mechanisms:
- noisy_epsilon_floor: random actions feed diverse replay buffer
- count bonus: UCB term biases greedy selection toward under-visited actions
- noisy nets: weight perturbation adds stochasticity to Q-values

select_action_inference (production) is unchanged — pure exploitation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-03-06 18:27:04 +01:00

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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