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Check evaluation after ttMove before doing a tt cut

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Passed STC
LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 239136 W: 62222 L: 61608 D: 115306
Ptnml(0-2): 675, 28046, 61525, 28634, 688
https://tests.stockfishchess.org/tests/view/681053293629b02d74b1668f

Passed LTC
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 448770 W: 115237 L: 114088 D: 219445
Ptnml(0-2): 177, 48128, 126619, 49291, 170
https://tests.stockfishchess.org/tests/view/681902de3629b02d74b16f6d

closes https://github.com/official-stockfish/Stockfish/pull/6069

Bench: 2035432
This commit is contained in:
Daniel Monroe
2025-05-19 07:37:15 +02:00
committed by Joost VandeVondele
parent 4f76768fcf
commit 6e9b5af0f0
1 changed files with 27 additions and 2 deletions
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src/search.cpp
+27 -2
View File
@@ -680,6 +680,8 @@ Value Search::Worker::search(
&& (ttData.bound & (ttData.value >= beta ? BOUND_LOWER : BOUND_UPPER))
&& (cutNode == (ttData.value >= beta) || depth > 5))
{
// If ttMove is quiet, update move sorting heuristics on TT hit
if (ttData.move && ttData.value >= beta)
{
@@ -696,7 +698,30 @@ Value Search::Worker::search(
// Partial workaround for the graph history interaction problem
// For high rule50 counts don't produce transposition table cutoffs.
if (pos.rule50_count() < 90)
return ttData.value;
{
if (depth >= 8 && ttData.move && pos.pseudo_legal(ttData.move) && pos.legal(ttData.move)
&& !is_decisive(ttData.value))
{
do_move(pos, ttData.move, st);
Key nextPosKey = pos.key();
auto [ttHitNext, ttDataNext, ttWriterNext] = tt.probe(nextPosKey);
ttDataNext.value =
ttHitNext ? value_from_tt(ttDataNext.value, ss->ply + 1, pos.rule50_count())
: VALUE_NONE;
undo_move(pos, ttData.move);
if (!is_valid(ttDataNext.value))
return ttData.value;
if (ttData.value >= beta && -ttDataNext.value >= beta)
return ttData.value;
if (ttData.value <= alpha && -ttDataNext.value <= alpha)
return ttData.value;
}
else
{
return ttData.value;
}
}
}
// Step 5. Tablebases probe
@@ -1233,7 +1258,7 @@ moves_loop: // When in check, search starts here
// std::clamp has been replaced by a more robust implementation.
Depth d = std::max(1, std::min(newDepth - r / 1024,
newDepth + !allNode + (PvNode && !bestMove)))
+ ((ss - 1)->isPvNode);
+ ((ss - 1)->isPvNode);
ss->reduction = newDepth - d;
value = -search<NonPV>(pos, ss + 1, -(alpha + 1), -alpha, d, true);