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| author | Scott Gasch <[email protected]> | 2026-08-29 19:25:30 -0700 |
|---|---|---|
| committer | Scott Gasch <[email protected]> | 2026-08-29 19:25:30 -0700 |
| commit | 4b99e893a2b423247fd20ab69c0346fcbe6bca81 (patch) | |
| tree | 32d435a7a89d5ac3628ce53ef5cd5313025d10f1 /src/genetic/Makefile | |
| parent | 0b12137376929d96da81cd088d3d288cb1eec32d (diff) | |
Ditch Texel-tuned eval constants for the pre-tuning hand-tuned baseline; fix a stale king-safety data bug found along the way.
The Texel/coordinate-descent auto-tuning pass (started at 29d73f4) left
several eval terms with non-monotonic or outright sign-flipped values
that several ASSERTs had to be silently commented out to tolerate
(e.g. BACKWARD_SHIELDED_BY_LOCATION scoring a structural pawn defect as
a +12..+17 bonus on most squares, PASSER_BONUS_AS_MATERIAL_COMES_OFF
staying flat until the defending side was down to almost nothing).
Restored all 54 differing constant tables to their last hand-tuned
values (commit df8facc, pre-dating 29d73f4) mechanically -- table
names/shapes are identical between the two commits, only values
differ, so this is a pure data restore with none of the surrounding
code-structure changes since df8facc reverted.
Also fixes a real bug found while investigating: pos->uPiecesPointingAtKing[]
was only refreshed inside EstimatePositionalScore's lazy-eval-margin
path (eval.c ~5648), but _EvalKing reads it unconditionally on every
full eval. Whenever a node's cheap material+pawn score wasn't close
enough to the alpha/beta window to trigger that lazy-margin branch, the
full eval proceeded straight to _EvalKing using a stale
uPiecesPointingAtKing value left over from a prior, unrelated node --
silent, intermittent noise in king-safety scoring on an unpredictable
subset of evaluations. Introduced 2026-08-24/26 (29d73f4, 7857096), so
it predates and was baked into the Texel tuning pass being reverted
here. Fixed by computing it once in an else branch when the lazy-margin
path isn't taken, so it's refreshed exactly once per full eval either
way (this is the innermost eval loop, so avoided doubling the cost on
the branch that already computes it).
sd10/sn5m results across the three curated suites (vs. head_reference,
the prior Texel-tuned HEAD):
sd10: ringers 9/11 (was 10), confident 85/90 (was 88), hard 23/90 (was 17) -- total 117 vs 115
sn5m: ringers 11/11 (was 10), confident 87/90 (was 89), hard 14/90 (was 13) -- total 112 vs 112
Net win at sd10, wash at sn5m, in both cases with a large swing toward
ecm_hard_quick -- consistent with hand-tuned values being more
internally coherent (monotonic curves, no sign flips, no double-counted
whole-position aggregates layered on top of already-summed per-item
terms) even though they were never retuned against this specific suite
or these specific opponents.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01M9ZDiJhiUajUxh95mTXCFJ
Diffstat (limited to 'src/genetic/Makefile')
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