From bbad001a4921e8351b42d6231b7d27c8c3ac9446 Mon Sep 17 00:00:00 2001 From: FauziAkram Date: Thu, 11 Sep 2025 03:04:53 +0300 Subject: [PATCH] Double PawnHistory size and update formula Doubling PAWN_HISTORY_SIZE to 1024. So with that, we can apply a stronger learning signal. The bonus/malus multipliers in the update_quiet_histories function have been increased accordingly. Passed STC: LLR: 2.97 (-2.94,2.94) <0.00,2.00> Total: 111008 W: 29136 L: 28708 D: 53164 Ptnml(0-2): 367, 12870, 28609, 13284, 374 https://tests.stockfishchess.org/tests/view/68c201d659efc3c96b61117e Passed LTC: LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 117210 W: 30142 L: 29664 D: 57404 Ptnml(0-2): 49, 12532, 32970, 13000, 54 https://tests.stockfishchess.org/tests/view/68c20a6259efc3c96b6111ef closes https://github.com/official-stockfish/Stockfish/pull/6306 Bench: 2788334 --- src/history.h | 2 +- src/search.cpp | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/history.h b/src/history.h index faf4af3d7..1f7abc542 100644 --- a/src/history.h +++ b/src/history.h @@ -33,7 +33,7 @@ namespace Stockfish { -constexpr int PAWN_HISTORY_SIZE = 512; // has to be a power of 2 +constexpr int PAWN_HISTORY_SIZE = 1024; // has to be a power of 2 constexpr int CORRECTION_HISTORY_SIZE = 32768; // has to be a power of 2 constexpr int CORRECTION_HISTORY_LIMIT = 1024; constexpr int LOW_PLY_HISTORY_SIZE = 5; diff --git a/src/search.cpp b/src/search.cpp index 0a4a390bb..25102b131 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1873,7 +1873,7 @@ void update_quiet_histories( int pIndex = pawn_history_index(pos); workerThread.pawnHistory[pIndex][pos.moved_piece(move)][move.to_sq()] - << (bonus * (bonus > 0 ? 704 : 439) / 1024) + 70; + << (bonus * (bonus > 0 ? 800 : 500) / 1024) + 70; } }