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Tune a few parameters related to evaluation
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based on a SPSA tune (using Autoselect)
https://tests.stockfishchess.org/tests/view/61d5aa63a314fed318a57046

passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.50>
Total: 61960 W: 16640 L: 16316 D: 29004
Ptnml(0-2): 278, 6934, 16204, 7314, 250
https://tests.stockfishchess.org/tests/view/61d7fe4af5fd40f357469a8d

passed LTC:
LLR: 2.97 (-2.94,2.94) <0.50,3.00>
Total: 79408 W: 21994 L: 21618 D: 35796
Ptnml(0-2): 106, 7887, 23331, 8285, 95
https://tests.stockfishchess.org/tests/view/61d836b7f5fd40f35746a3d5

closes #3883

Bench: 4266621
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vondele committed Jan 8, 2022
1 parent 2efda17 commit 9ad0ea7
Showing 1 changed file with 7 additions and 7 deletions.
14 changes: 7 additions & 7 deletions src/evaluate.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -192,8 +192,8 @@ using namespace Trace;
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
Expand Down Expand Up @@ -1087,10 +1087,10 @@ Value Eval::evaluate(const Position& pos) {
// 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
useClassical = abs(v) >= 300;
useClassical = abs(v) >= 298;
}

// If result of a classical evaluation is much lower than threshold fall back to NNUE
Expand All @@ -1101,17 +1101,17 @@ Value Eval::evaluate(const Position& pos) {
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 = abs(nnue - psq) / 256;
int complexity = 35 * abs(nnue - psq) / 256;

optimism *= (1 + complexity);
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 * (207 - pos.rule50_count()) / 207;
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);
Expand Down

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