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Use game-cycle detection to update corrhist. #429

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Merged
TheRealGioviok merged 2 commits into from
Sep 23, 2026
Merged

Use game-cycle detection to update corrhist. #429

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ebd41e1
Use game-cycle detection to update corrhist.
cosmobobak Sep 21, 2026
32725f3
Bench: 12869976
TheRealGioviok Sep 22, 2026
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20 changes: 15 additions & 5 deletions src/search.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -502,6 +502,8 @@ Value Worker::search(
return 0;
}

bool is_in_check = pos.is_in_check();

// Draw checks
if (!ROOT_NODE) {
// Repetition check
Expand All @@ -518,6 +520,15 @@ Value Worker::search(
}
// Upcoming repetition detection
if (alpha < 0 && repetition_info.has_game_cycle(pos, static_cast<usize>(ply))) {
if (!is_in_check) {
auto raw_eval = evaluate(pos);
auto correction = m_td.history.get_correction(pos);
auto eval = adj_shuffle(pos, raw_eval) + correction;
if (eval < 0) {
m_td.history.update_correction_history(pos, depth, -eval);
}
}

alpha = 0;
if (alpha >= beta) {
return alpha;
Expand Down Expand Up @@ -600,11 +611,10 @@ Value Worker::search(
: tt_data ? tt_data->move
: Move::none();

bool is_in_check = pos.is_in_check();
bool improving = false;
Value correction = 0;
Value raw_eval = -VALUE_INF;
ss->static_eval = -VALUE_INF;
bool improving = false;
Value correction = 0;
Value raw_eval = -VALUE_INF;
ss->static_eval = -VALUE_INF;
if (!is_in_check) {
correction = excluded ? 0 : m_td.history.get_correction(pos);
raw_eval = tt_data && !is_decisive_score(tt_data->eval) ? tt_data->eval : evaluate(pos);
Expand Down
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