Phase A NNUE: feature-indexing spec, annotation/training pipeline, dump nnuefeatures

2026-10-15T20:11:22Z

Builds out the NNUE Phase A prototype per docs/NNUE.md: - src/nnuefeatures.c: standalone HalfKAv2_hm feature-index reference implementation (new `dump nnuefeatures` command), sourced from Stockfish's half_ka_v2_hm.{h,cpp} (sf_16 tag), including the 0x88->64 square conversion typhoon's own board representation needs. - annotate_pgns/: sharded TWIC/self-play annotation harness (annotate.py), position extraction, quiet-position filtering (flat and game-shaped, plus an upstream --prefilter-quiet option), train/holdout game-level stratified split, WDL-sigmoid K fitting, the Python HalfKAv2_hm reference encoder (nnue_feature_spec.py) and its bit-for-bit cross-checker against the C side (cross_check_features.py), and a first PyTorch training pipeline (nnue_model.py, nnue_train.py, build_training_tensors.py) -- a 256x2-32-32-1-ish net trained locally on CPU against ~1.85M quiet TWIC positions as a pipeline/framework validation pass. - Finish an in-progress InitMagic/InitLMRTable/InitEval -> InitializeBitboardMagic/InitializeLMRTable/InitializeEval rename: chess.h's prototypes hadn't been updated to match the already-renamed definitions/call sites, leaving 4 implicit-function-declaration warnings. - tests/arasan.epd: new curated EPD suite. - docs/: add the project's design docs (previously untracked). Co-Authored-By: Claude Sonnet 5

typhoon.git/annotate_pgns/nnue_feature_spec.py, branch master

Phase A NNUE: feature-indexing spec, annotation/training pipeline, dump nnuefeatures