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Introduce Material Correction History

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Idea from Caissa (https://github.com/Witek902/Caissa) chess engine.

Add a secondary correction history indexed by the material key of a position.
The material key is the zobrist hash representing the number of pieces left in a
position.

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 189472 W: 49360 L: 48813 D: 91299
Ptnml(0-2): 666, 22453, 47953, 22996, 668
https://tests.stockfishchess.org/tests/view/66cbddafbf8c9d8780fda9f1

Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 224190 W: 57022 L: 56312 D: 110856
Ptnml(0-2): 197, 24723, 61540, 25443, 192
https://tests.stockfishchess.org/tests/view/66cd529bbf8c9d8780fdab4c

closes https://github.com/official-stockfish/Stockfish/pull/5556

Bench: 1462697
This commit is contained in:
Shawn Xu
2024-08-23 17:13:49 -07:00
committed by Disservin
parent 4fb04eb3df
commit ddc9f48bc3
3 changed files with 36 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/search.cpp
+8 -3
View File
@@ -81,7 +81,10 @@ constexpr int futility_move_count(bool improving, Depth depth) {
// Add correctionHistory value to raw staticEval and guarantee evaluation
// does not hit the tablebase range.
Value to_corrected_static_eval(Value v, const Worker& w, const Position& pos) {
auto cv = w.correctionHistory[pos.side_to_move()][pawn_structure_index<Correction>(pos)];
const auto pcv =
w.pawnCorrectionHistory[pos.side_to_move()][pawn_structure_index<Correction>(pos)];
const auto mcv = w.materialCorrectionHistory[pos.side_to_move()][material_index(pos)];
const auto cv = (2 * pcv + mcv) / 3;
v += 66 * cv / 512;
return std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
}
@@ -487,7 +490,8 @@ void Search::Worker::clear() {
mainHistory.fill(0);
captureHistory.fill(-700);
pawnHistory.fill(-1188);
correctionHistory.fill(0);
pawnCorrectionHistory.fill(0);
materialCorrectionHistory.fill(0);
for (bool inCheck : {false, true})
for (StatsType c : {NoCaptures, Captures})
@@ -1390,7 +1394,8 @@ moves_loop: // When in check, search starts here
{
auto bonus = std::clamp(int(bestValue - ss->staticEval) * depth / 8,
-CORRECTION_HISTORY_LIMIT / 4, CORRECTION_HISTORY_LIMIT / 4);
thisThread->correctionHistory[us][pawn_structure_index<Correction>(pos)] << bonus;
thisThread->pawnCorrectionHistory[us][pawn_structure_index<Correction>(pos)] << bonus;
thisThread->materialCorrectionHistory[us][material_index(pos)] << bonus;
}
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);