diff --git a/src/movepick.cpp b/src/movepick.cpp index 1d1aef0f313..0649518938a 100644 --- a/src/movepick.cpp +++ b/src/movepick.cpp @@ -179,7 +179,7 @@ void MovePicker::score() { : pt == ROOK && bool(to & threatenedByMinor) ? 24335 : 0); - if (ply < 4) + if (ply < LOW_PLY_HISTORY_SIZE) m.value += 8 * (*lowPlyHistory)[ply][m.from_to()] / (1 + 2 * ply); } diff --git a/src/movepick.h b/src/movepick.h index 9a68aaa1d7a..5c312531ef1 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -37,6 +37,7 @@ namespace Stockfish { constexpr int PAWN_HISTORY_SIZE = 512; // 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 = 4; static_assert((PAWN_HISTORY_SIZE & (PAWN_HISTORY_SIZE - 1)) == 0, "PAWN_HISTORY_SIZE has to be a power of 2"); @@ -137,7 +138,7 @@ using ButterflyHistory = Stats; +using LowPlyHistory = Stats; // CapturePieceToHistory is addressed by a move's [piece][to][captured piece type] using CapturePieceToHistory = Stats; diff --git a/src/search.cpp b/src/search.cpp index 647bae764f3..6e513b458ff 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1851,7 +1851,7 @@ void update_quiet_histories( Color us = pos.side_to_move(); workerThread.mainHistory[us][move.from_to()] << bonus; - if (ss->ply < 4) + if (ss->ply < LOW_PLY_HISTORY_SIZE) workerThread.lowPlyHistory[ss->ply][move.from_to()] << bonus; update_continuation_histories(ss, pos.moved_piece(move), move.to_sq(), bonus);