jgrusewski cc96dd7fd3 fix(F4/F5/D6): kernel buffer-stride bug + D6 warmup gate
Root cause of L40S segfault (train-tgdlq workflow, commit 0d639dfe9):

1. F4 (IB) and F5 (barrier) gradient kernels indexed cql_d_adv_logits and
   on_b_logits_buf with stride b0_size (4) instead of total_actions (13).
   The buffer is sized [B, total_actions, num_atoms]. Writes for batch i>0
   landed in other actions'/batches' gradient slots — corrupting CQL gradient
   for every batch beyond the first. After cuBLAS backward, weights diverged
   in undefined ways; validation forward then segfaulted reading NaN-laced
   parameters in GpuBacktestEvaluator init.

   Fix: add `total_actions` kernel parameter (int), use it as the full stride
   for adv_row and d_adv_a pointer arithmetic; keep b0_size as the loop
   bound (direction-branch-only update). All three launch sites updated:
   inlined F5 launch in apply_cql_gradient, inlined F4 launch alongside,
   and the standalone inject_barrier_into_cql_d_logits method.

2. D6 ensemble oracle fired at epoch 0 because per-branch Q-gaps are all 0
   at random init (range = 0 → score = 1.0 → plasticity trigger).
   Shrink-and-perturb ran immediately, then again next epoch, etc. Gate
   behind `learning_health.epoch > 5` (3 warmup + 2 buffer epochs for Q to
   move) so the oracle only fires on post-warmup real collapse, not
   untrained networks.

Both bugs are regressions from today's work — F4/F5 introduced yesterday,
D6 became live after the ens_disagreement real-signal fix in d9d35b6fa.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-20 22:03:45 +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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Rust 88.2%
Cuda 7.7%
Python 1.3%
Shell 1.1%
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