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Fix wrong mate/tb scores from probCut

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This fixes returning wrong mated-in scores, or losing a proven mate-in score
from probCut after recent tweaks. The issue reported by @cj5716 on discord.

Passed non-reg STC:
https://tests.stockfishchess.org/tests/view/6583c36b5457644dc9843afe
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 295936 W: 75011 L: 75075 D: 145850
Ptnml(0-2): 978, 33947, 78146, 33955, 942

Passed non-reg LTC:
https://tests.stockfishchess.org/tests/view/658513075457644dc98451cd
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 55932 W: 13970 L: 13786 D: 28176
Ptnml(0-2): 33, 5933, 15837, 6143, 20

closes https://github.com/official-stockfish/Stockfish/pull/4933

Bench: 1308739
This commit is contained in:
peregrineshahin 2023-12-21 07:44:32 +03:00 • committed by Disservin
parent fbdf5d94a9
commit 3f5adc037e
1 changed files with 4 additions and 3 deletions
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7
src/search.cpp
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@ -854,7 +854,7 @@ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, boo
// So effective depth is equal to depth - 3
&& !(tte->depth() >= depth - 3 && ttValue != VALUE_NONE && ttValue < probCutBeta))
{
assert(probCutBeta < VALUE_INFINITE);
assert(probCutBeta < VALUE_INFINITE && probCutBeta > beta);
MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
@ -888,7 +888,8 @@ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, boo
// Save ProbCut data into transposition table
tte->save(posKey, value_to_tt(value, ss->ply), ss->ttPv, BOUND_LOWER, depth - 3,
move, ss->staticEval);
return value - (probCutBeta - beta);
return std::abs(value) < VALUE_TB_WIN_IN_MAX_PLY ? value - (probCutBeta - beta)
: value;
}
}
@ -1613,7 +1614,7 @@ Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) {
return mated_in(ss->ply); // Plies to mate from the root
}
if (abs(bestValue) < VALUE_TB_WIN_IN_MAX_PLY)
if (std::abs(bestValue) < VALUE_TB_WIN_IN_MAX_PLY)
bestValue = bestValue >= beta ? (3 * bestValue + beta) / 4 : bestValue;
// Save gathered info in transposition table