jgrusewski 39f90f3723 fix(rl): EMA-streaming variance + kurtosis kernels fix b_size=1 dead inputs
mjzfk + pdgxn diags showed `advantage_var_ratio` and `td_kurtosis`
identically 0 for 100% of every 50k-step smoke. Root cause: the
per-batch `rl_var_over_abs_mean_b` and `rl_kurtosis_b` kernels are
mathematically undefined at b_size=1 (variance of a single sample is
zero; kurtosis of a single sample is 0/0). The kernels correctly
returned 0 in that case but the downstream `rl_rollout_steps` and
`rl_per_alpha` controllers then never saw signal and pegged at MIN
(2048 / 0.4) for the entire run.

## Fix: time-axis Welford-EMA streaming

Replace per-batch reduction with per-step EMA-streaming moments
maintained in ISV slots:

  rl_var_over_abs_mean_streaming.cu — maintains streaming mean + M2,
  emits var/|mean| each step. Welford-EMA on the batch-mean of
  advantages_d (one value at b_size=1, or a single batch reduction
  at b_size>1) folded into the time-axis estimator.

  rl_kurtosis_streaming.cu — maintains streaming mean + M2 + M4,
  emits M4/M2² (Pearson kurtosis) each step. Same Welford-EMA shape
  applied to td_per_sample_d batch mean.

Both kernels use STREAM_ALPHA = 0.05 (matches LR_LOSS_EMA_ALPHA —
half-life ≈ 14 steps) so the time estimator smooths over noisy
per-step batch-mean observations. The kernel writes the smoothed
estimate DIRECTLY to the controller-input ISV slot
(RL_ADVANTAGE_VAR_RATIO_EMA_INDEX = 421,
 RL_TD_KURTOSIS_EMA_INDEX = 422); the prior downstream
ema_update_per_step calls for these two signals are REMOVED — the
streaming kernel IS the EMA.

## ISV slot allocation

5 new state slots holding the streaming-mean / M2 / M4 per-stream
state. RL_SLOTS_END: 442 → 447.

  RL_ADV_VAR_STREAM_MEAN_INDEX        = 442  (streaming mean of advantages)
  RL_ADV_VAR_STREAM_M2_INDEX          = 443  (streaming M2 of advantages)
  RL_TD_KURT_STREAM_MEAN_INDEX        = 444  (streaming mean of TD-CE)
  RL_TD_KURT_STREAM_M2_INDEX          = 445
  RL_TD_KURT_STREAM_M4_INDEX          = 446

Per `pearl_first_observation_bootstrap`: sentinel-zero state
triggers replace-direct first-observation bootstrap (the first
step seeds μ = batch_mean, M2 = 0, M4 = 0 — subsequent steps blend).

Per `pearl_blend_formulas_must_have_permanent_floor`: var/|mean|
denominator floored at 1e-6, M2² denominator floored at 1e-12 —
prevents div-by-zero blow-up when streaming mean / variance is
genuinely zero (cold-start or quiet regime).

## Files

  * crates/ml-alpha/cuda/rl_var_over_abs_mean_streaming.cu  — new
  * crates/ml-alpha/cuda/rl_kurtosis_streaming.cu           — new
  * crates/ml-alpha/cuda/rl_var_over_abs_mean_b.cu          — deleted
  * crates/ml-alpha/cuda/rl_kurtosis_b.cu                   — deleted
  * crates/ml-alpha/src/rl/isv_slots.rs                     — +5 slots
  * crates/ml-alpha/src/trainer/integrated.rs               — rewired
                                                              launchers,
                                                              dropped
                                                              redundant
                                                              ema_update
                                                              calls
  * crates/ml-alpha/build.rs                                — swapped
                                                              cubin
                                                              entries

## Verified gates (local sm_86)

  G1 isv_bootstrap   
  G3 controllers     
  G4 target_update   
  integrated_smoke   

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-23 21:53:56 +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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