jgrusewski ab9c7e43a8 delete(dqn): D.7 liquid_mod audit — ODE identity, remove from c51_grad + experience kernels
The liquid_tau_rk4_step kernel modelled f(x) = (1/tau)*(1-x), which has
fixed point x=1.0 for any tau. liquid_mod_buf was initialised to [1.0;4]
and the dynamics could never move it away from that fixed point since every
kernel call reduces to f(1.0)=0 (no perturbation path exists). The
velocity_mod multiplier in c51_grad_kernel was therefore always 1.0 — a
mathematical identity with zero measurable effect on spread_scale.

Additionally, no ISV slot existed for liquid_mod (violates §4.C.6
GPU-drives spec), and the associated LiquidTrainableAdapter supervised
path was never wired into the DQN backward pass.

Decision C (delete): remove liquid_tau_rk4_step kernel (experience_kernels.cu),
liquid_mod param + velocity_mod line (c51_grad_kernel.cu), liquid_mod_buf
allocation, liquid_tau_rk4_kernel field, update_liquid_tau() method and its
call site in update_eval_v_range() (gpu_dqn_trainer.rs). per_branch_q_gap_ema_buf
is retained — it is used independently for trajectory backtracking state
snapshot/restore. Supervised LiquidTrainableAdapter unchanged.

cargo check -p ml: 8 warnings (baseline), 0 errors.
Audit docs updated: dqn-wire-up-audit.md + ml-supervised-to-dqn-concept-audit.md.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-24 20:18:59 +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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Python 1.3%
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