jgrusewski 82dca76dae feat(explainability): post-hoc IG diagnostic CLI for DQN checkpoints
Adds `ig_diag` binary under ml-explainability/src/bin/ that runs
Integrated Gradients on a trained DQN safetensors checkpoint and
writes a per-feature attribution report as JSON. Designed for offline
model inspection, not the inference hot path.

Forward target: mean(Q[direction, 0..4]), which simplifies to V(s)
under the dueling identity (mean of centered advantages is zero by
the identifiability constraint). Smooth, no argmax discontinuity,
well-posed for IG.

Regime-head handling: loads only the `trending__`-prefixed weights
(matches RegimeConditionalDQN::load_from_merged_safetensors). Full
multi-head attribution is a future extension.

CLI args:
  --checkpoint PATH        safetensors file
  --states auto|PATH       `auto` samples from test_data/feature-cache/
                           *.fxcache; otherwise a JSON file containing
                           { "states": [[f32; STATE_DIM], ...] }
  --feature-names PATH     JSON array of STATE_DIM names (optional)
  --num-steps N            IG Riemann steps (default 50)
  --output PATH            output JSON (default ig_report.json)
  --auto-samples N         fxcache sample count (default 16)
  --seed N                 LCG seed for reproducibility (default 42)

Output JSON schema:
  {
    "schema_version": 1,
    "checkpoint", "num_steps", "state_dim", "num_states",
    "forward_target", "regime_head",
    "features": [ { "name", "mean_abs", "stddev", "mean_signed" } ],
    "top_10_by_mean_abs": [...],
    "completeness": {
      "worst_relative_error": f64,
      "per_state": [ { "state_idx", "sum_attributions",
                       "f_input_minus_f_baseline", "relative_error" } ]
    }
  }

NoisyNet is disabled on both the Q-network and target network before
IG runs so attributions are deterministic (same checkpoint + states +
num_steps = bit-identical attributions).

Gated behind the `ig-diag-cli` Cargo feature (optional Cargo binary
feature, not a runtime flag) because the binary depends on ml-dqn.
Cannot depend on `ml` due to a cyclic dependency (ml already depends
on ml-explainability). To avoid pulling in the heavy `ml` crate, the
fxcache header parser is reimplemented inline in the binary (~80 LOC,
matches ml/src/fxcache.rs byte-for-byte for v4 files).

Tests:
- tests/ig_diag_cli_integration.rs: end-to-end test that builds a
  DQN, saves a checkpoint, writes a states JSON, invokes the binary
  via std::process::Command, parses the output, asserts schema +
  completeness axiom (worst relative error < 5%). Gated with
  #[cfg(all(feature = "cuda", feature = "ig-diag-cli"))] + #[ignore]
  because it needs CUDA + the binary pre-built.

Build/run:
  cargo build --release -p ml-explainability \
    --features ig-diag-cli --bin ig_diag
  cargo test -p ml-explainability --features ig-diag-cli \
    --test ig_diag_cli_integration -- --ignored --nocapture

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-23 10:35:48 +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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