jgrusewski 797f8bf326 feat(dqn): SP1 Phase B accessors — backward-buffer NaN check pointers
Adds 5 new pub(crate) accessor methods exposing backward-path buffer
device pointers for Task 4's per-step NaN checks (slots 24, 25, 28,
29, 30 per audit per-slot table at docs/dqn-backward-nan-audit.md
:530-548):

GpuDqnTrainer (4 new):
- d_value_logits_buf_ptr  (slot 24 — post-c51_grad value gradient)
- d_adv_logits_buf_ptr    (slot 25 — post-c51_grad branch advantage)
- cql_d_value_logits_ptr  (slot 29 — CQL gradient output)
- aux_dh_s2_nb_buf_ptr    (slot 30 — aux next-bar backward dh_s2)

GpuIqnHead (1 new):
- d_branch_logits_buf_ptr (slot 28 — production IQN backward output,
                           iqn_quantile_huber_loss)

Slot 27 (iqn_d_h_s2_buf) reuses existing GpuIqnHead::d_h_s2_raw_ptr()
at gpu_iqn_head.rs:1660 — no new method per feedback_no_legacy_aliases:
the existing accessor is already public and sufficient; renaming +
chasing the single call site adds churn without value.

Slots 26, 32, 33-35 reuse pre-existing handles:
- 26: self.ptrs.iqn_trunk_m
- 32: self.bn_d_concat_buf() (existing, returns &CudaSlice<f32>)
- 33-35: self.ptrs.bw_d_h_s2 (3 different Task 4 call sites)

Slot 31 (ensemble_d_logits_buf) deferred per Task 2 commit 387335e2b
(cross-struct on FusedDqnTraining).

DEVIATION FROM PLAN: the plan called for "delegate accessors on
GpuDqnTrainer for slots 27/28" — structurally invalid because
GpuDqnTrainer does NOT own GpuIqnHead. The IQN head is owned by
FusedTrainingCtx (fused_training.rs:289) alongside the trainer at
line 234. The audit's per-slot accessor table (lines 535-536) is
correct: accessors land on GpuIqnHead. Task 4's
run_nan_checks_post_backward will receive IQN pointers as u64
arguments from the FusedTrainingCtx call site — same pattern already
in use at gpu_dqn_trainer.rs:6843
(apply_iqn_trunk_gradient(&mut self, iqn_d_h_s2_ptr: u64, ...)).

NO new scratch buffer added — the plan's bw_d_h_s2_pre_saxpy scratch
+ DtoD-copy approach was superseded by the audit's 3-call-site
reformulation. Slots 33/34/35 are post-main / post-aux / post-iqn
snapshots of the same bw_d_h_s2 (one buffer, three Task 4 invocations).

Pattern follows commit e9096c7be's GRN-block accessors (concise
pub(crate) fn name_ptr(&self) -> u64 with doc-comment referencing
slot number + audit doc + buffer semantics). Additive — no behavioral
change; new accessors consumed by Task 4's NaN check call sites.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-30 00:17:39 +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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Cuda 7.7%
Python 1.3%
Shell 1.1%
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