jgrusewski 7f92fa242c cleanup: wire td_error ISV scratch + rewrite stale TODOs declaratively
Part A of pre-L40S cleanup.

1. Wire td_error batch mean into ISV scratch (gpu_dqn_trainer.rs):
   `launch_loss_reduce` now runs the generic `c51_loss_reduce` kernel a
   second time over `td_errors_buf` into `td_error_scratch_dev_ptr`.
   ISV[2] (TD-error EMA in `isv_signal_update`) was previously reading
   a zero-initialised scratch and accumulated a constant-zero signal.
   This was a genuinely missing kernel writeback — the C51 loss kernel
   was already emitting per-sample |TD-error| into `td_errors_buf`
   (c51_loss_kernel.cu:1096), it just wasn't being batch-reduced.

   Reuses the existing `c51_loss_reduce` (generic mean-reduction, single
   block, deterministic) rather than adding a new kernel — no new CUDA
   surface, no ABI change.

2. Remove 2 stale TODOs from batched_backward.rs docstrings that
   described a migration that's actually complete:
   - Module docstring said "dqn_backward_kernel (atomicAdd path)
     remains active" — the atomicAdd kernel has been removed; cuBLAS
     backward is wired via launch_cublas_backward.
   - `backward_full` docstring said "gated behind TODO" — the function
     is actively called from the fused training step.

3. Rewrite 2 ISV scratch field comments as declarative: td_error_scratch
   is now wired (as per change 1); ensemble_var_scratch remains
   zero-initialised and its comment honestly describes that consumers
   (ISV[3] and [4]) treat it as unavailable. Per feedback_no_todo_fixme.md,
   replaces the TODO(isv) markers with declarative descriptions of
   current behaviour. Future wiring is tracked in the plan, not in code
   aspirational markers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-23 08:21:03 +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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