/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
+ Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
namespace {
// Threshold for lazy and space evaluation
- constexpr Value LazyThreshold1 = Value(3130);
- constexpr Value LazyThreshold2 = Value(2204);
+ constexpr Value LazyThreshold1 = Value(3631);
+ constexpr Value LazyThreshold2 = Value(2084);
constexpr Value SpaceThreshold = Value(11551);
// KingAttackWeights[PieceType] contains king attack weights by piece type
&& pos.piece_on(SQ_G7) == B_PAWN)
correction += CorneredBishop;
- return pos.side_to_move() == WHITE ? Value(5 * correction)
- : -Value(5 * correction);
+ return pos.side_to_move() == WHITE ? Value(3 * correction)
+ : -Value(3 * correction);
}
} // namespace Eval
Value Eval::evaluate(const Position& pos) {
Value v;
+ bool useClassical = false;
- // Deciding between classical and NNUE eval: for high PSQ imbalance we use classical,
+ // Deciding between classical and NNUE eval (~10 Elo): for high PSQ imbalance we use classical,
// but we switch to NNUE during long shuffling or with high material on the board.
-
if ( !useNNUE
- || abs(eg_value(pos.psq_score())) * 5 > (850 + pos.non_pawn_material() / 64) * (5 + pos.rule50_count()))
+ || abs(eg_value(pos.psq_score())) * 5 > (849 + pos.non_pawn_material() / 64) * (5 + pos.rule50_count()))
+ {
v = Evaluation<NO_TRACE>(pos).value(); // classical
- else
+ useClassical = abs(v) >= 298;
+ }
+
+ // If result of a classical evaluation is much lower than threshold fall back to NNUE
+ if (useNNUE && !useClassical)
{
- int scale = 883
- + 32 * pos.count<PAWN>()
- + 32 * pos.non_pawn_material() / 1024;
+ Value nnue = NNUE::evaluate(pos, true); // NNUE
+ int scale = 1136 + 20 * pos.non_pawn_material() / 1024;
+ Color stm = pos.side_to_move();
+ Value optimism = pos.this_thread()->optimism[stm];
+ Value psq = (stm == WHITE ? 1 : -1) * eg_value(pos.psq_score());
+ int complexity = 35 * abs(nnue - psq) / 256;
- v = NNUE::evaluate(pos, true) * scale / 1024; // NNUE
+ optimism = optimism * (44 + complexity) / 32;
+ v = (nnue + optimism) * scale / 1024 - optimism;
if (pos.is_chess960())
v += fix_FRC(pos);
}
// Damp down the evaluation linearly when shuffling
- v = v * (100 - pos.rule50_count()) / 100;
+ v = v * (208 - pos.rule50_count()) / 208;
// Guarantee evaluation does not hit the tablebase range
v = std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
std::memset(scores, 0, sizeof(scores));
- pos.this_thread()->trend = SCORE_ZERO; // Reset any dynamic contempt
- pos.this_thread()->bestValue = VALUE_ZERO; // Reset bestValue for lazyEval
+ // Reset any global variable used in eval
+ pos.this_thread()->trend = SCORE_ZERO;
+ pos.this_thread()->bestValue = VALUE_ZERO;
+ pos.this_thread()->optimism[WHITE] = VALUE_ZERO;
+ pos.this_thread()->optimism[BLACK] = VALUE_ZERO;
v = Evaluation<TRACE>(pos).value();