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Introduce continuation correction history based on ply-1, ply-2 #432

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Merged
TheRealGioviok merged 1 commit into from
Oct 19, 2026
Merged

Introduce continuation correction history based on ply-1, ply-2 #432

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20 changes: 18 additions & 2 deletions src/history.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,16 @@ void History::update_noisy_stats(const Position& pos, Move move, i32 bonus) {
bonus);
}

void History::update_correction_history(const Position& pos, i32 depth, i32 diff) {
static i32* get_cont_corr_slot(i32 ply, const Search::Stack* ss) {
if (ply < 2 || (ss - 2)->cont_corr_entry == nullptr || (ss - 1)->move == Move::none()) {
return nullptr;
}
usize prev_pt = static_cast<usize>((ss - 1)->moved_piece) - static_cast<usize>(PieceType::Pawn);
return &(*(ss - 2)->cont_corr_entry)[prev_pt][(ss - 1)->move.to().raw];
}

void History::update_correction_history(
const Position& pos, i32 depth, i32 diff, i32 ply, const Search::Stack* ss) {
usize side_index = static_cast<usize>(pos.active_color());
u64 pawn_key = pos.get_pawn_key();
u64 white_non_pawn_key = pos.get_non_pawn_key(Color::White);
Expand Down Expand Up @@ -120,9 +129,12 @@ void History::update_correction_history(const Position& pos, i32 depth, i32 diff
update_entry(m_non_pawn_corr_hist[1][side_index][black_non_pawn_index]);
update_entry(m_major_corr_hist[side_index][major_index]);
update_entry(m_minor_corr_hist[side_index][minor_index]);
if (i32* cont_corr = get_cont_corr_slot(ply, ss)) {
update_entry(*cont_corr);
}
}

i32 History::get_correction(const Position& pos) const {
i32 History::get_correction(const Position& pos, i32 ply, const Search::Stack* ss) const {
usize side_index = static_cast<usize>(pos.active_color());
u64 pawn_key = pos.get_pawn_key();
u64 white_non_pawn_key = pos.get_non_pawn_key(Color::White);
Expand All @@ -143,6 +155,9 @@ i32 History::get_correction(const Position& pos) const {
correction += m_non_pawn_corr_hist[1][side_index][black_non_pawn_index];
correction += m_major_corr_hist[side_index][major_index];
correction += m_minor_corr_hist[side_index][minor_index];
if (const i32* cont_corr = get_cont_corr_slot(ply, ss)) {
correction += *cont_corr;
}

return correction / CORRECTION_HISTORY_GRAIN;
}
Expand All @@ -156,6 +171,7 @@ void History::clear() {
std::memset(&m_non_pawn_corr_hist[1], 0, sizeof(CorrectionHistory));
std::memset(&m_major_corr_hist, 0, sizeof(CorrectionHistory));
std::memset(&m_minor_corr_hist, 0, sizeof(CorrectionHistory));
std::memset(&m_cont_corr_hist, 0, sizeof(ContCorrHistory));
}

} // namespace Clockwork
21 changes: 16 additions & 5 deletions src/history.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6,9 +6,11 @@

namespace Clockwork {

using MainHistory = std::array<std::array<std::array<i32, 4>, 4096>, 2>;
using ContHistEntry = std::array<std::array<std::array<i32, 64>, 6>, 2>;
using ContHistory = std::array<std::array<std::array<ContHistEntry, 64>, 6>, 2>;
using MainHistory = std::array<std::array<std::array<i32, 4>, 4096>, 2>;
using ContHistEntry = std::array<std::array<std::array<i32, 64>, 6>, 2>;
using ContHistory = std::array<std::array<std::array<ContHistEntry, 64>, 6>, 2>;
using ContCorrEntry = std::array<std::array<i32, 64>, 6>;
using ContCorrHistory = std::array<std::array<std::array<ContCorrEntry, 64>, 6>, 2>;
// king can't get captured
using CaptHistory = std::array<std::array<std::array<std::array<i32, 64>, 6>, 6>, 2>;
using CorrectionHistory = std::array<std::array<i32, 16384>, 2>;
Expand All @@ -34,16 +36,24 @@
return m_cont_hist[stm_idx][pt_idx][move.to().raw];
}

ContCorrEntry& get_cont_corr_entry(const Position& pos, Move move) {
usize stm_idx = static_cast<usize>(pos.active_color());
PieceType pt = pos.piece_at(move.from());
usize pt_idx = static_cast<usize>(pt) - static_cast<usize>(PieceType::Pawn);
return m_cont_corr_hist[stm_idx][pt_idx][move.to().raw];
}

i32 get_conthist(const Position& pos, Move move, i32 ply, Search::Stack* ss) const;
i32 get_quiet_stats(const Position& pos, Move move, i32 ply, Search::Stack* ss) const;
void update_cont_hist(const Position& pos, Move move, i32 ply, Search::Stack* ss, i32 bonus);
void update_quiet_stats(const Position& pos, Move move, i32 ply, Search::Stack* ss, i32 bonus);

i32 get_noisy_stats(const Position& pos, Move move) const;

Check warning on line 51 in src/history.hpp

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GitHub Actions / Linter / cpp-linter

src/history.hpp:51:5 [modernize-use-nodiscard] 

function 'get_noisy_stats' should be marked [[nodiscard]]
void update_noisy_stats(const Position& pos, Move move, i32 bonus);

void update_correction_history(const Position& pos, i32 depth, i32 diff);
i32 get_correction(const Position& pos) const;
void update_correction_history(
const Position& pos, i32 depth, i32 diff, i32 ply, const Search::Stack* ss);
i32 get_correction(const Position& pos, i32 ply, const Search::Stack* ss) const;

void clear();

Expand All @@ -64,6 +74,7 @@
std::array<CorrectionHistory, 2> m_non_pawn_corr_hist = {};
CorrectionHistory m_major_corr_hist = {};
CorrectionHistory m_minor_corr_hist = {};
ContCorrHistory m_cont_corr_hist = {};
};

} // namespace Clockwork
29 changes: 24 additions & 5 deletions src/search.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -522,10 +522,10 @@ Value Worker::search(
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 correction = m_td.history.get_correction(pos, ply, ss);
auto eval = adj_shuffle(pos, raw_eval) + correction;
if (eval < 0) {
m_td.history.update_correction_history(pos, depth, -eval);
m_td.history.update_correction_history(pos, depth, -eval, ply, ss);
}
}

Expand Down Expand Up @@ -616,7 +616,7 @@ Value Worker::search(
Value raw_eval = -VALUE_INF;
ss->static_eval = -VALUE_INF;
if (!is_in_check) {
correction = excluded ? 0 : m_td.history.get_correction(pos);
correction = excluded ? 0 : m_td.history.get_correction(pos, ply, ss);
raw_eval = tt_data && !is_decisive_score(tt_data->eval) ? tt_data->eval : evaluate(pos);
ss->static_eval = adj_shuffle(pos, raw_eval) + correction;
improving =
Expand Down Expand Up @@ -711,6 +711,9 @@ Value Worker::search(
for (Move m = moves.next(); m != Move::none(); m = moves.next()) {

ss->cont_hist_entry = &m_td.history.get_cont_hist_entry(pos, m);
ss->move = m;
ss->moved_piece = pos.piece_at(m.from());
ss->cont_corr_entry = &m_td.history.get_cont_corr_entry(pos, m);
Position pos_after = pos.move(m, m_td.push_psqt_state(), &m_searcher.tt);
repetition_info.push(pos_after.get_hash_key(), pos.is_reversible(m));

Expand All @@ -726,6 +729,9 @@ Value Worker::search(
repetition_info.pop();
m_td.pop_psqt_state();
ss->cont_hist_entry = nullptr;
ss->move = Move::none();
ss->moved_piece = PieceType::None;
ss->cont_corr_entry = nullptr;

if (probcut_value >= probcut_beta) {
m_searcher.tt.store(pos, ply, raw_eval, m, probcut_value, probcut_depth, false,
Expand Down Expand Up @@ -878,6 +884,9 @@ Value Worker::search(

// Do move
ss->cont_hist_entry = &m_td.history.get_cont_hist_entry(pos, m);
ss->move = m;
ss->moved_piece = pos.piece_at(m.from());
ss->cont_corr_entry = &m_td.history.get_cont_corr_entry(pos, m);

Position pos_after = pos.move(m, m_td.push_psqt_state(), &m_searcher.tt);
moves_played++;
Expand Down Expand Up @@ -986,6 +995,9 @@ Value Worker::search(
repetition_info.pop();
m_td.pop_psqt_state();
ss->cont_hist_entry = nullptr;
ss->move = Move::none();
ss->moved_piece = PieceType::None;
ss->cont_corr_entry = nullptr;

if (m_stopped) {
return 0;
Expand Down Expand Up @@ -1099,7 +1111,8 @@ Value Worker::search(
&& !(best_move != Move::none() && (best_move.is_capture() || best_move.is_promotion()))
&& !((bound == Bound::Lower && best_value <= ss->static_eval)
|| (bound == Bound::Upper && best_value >= ss->static_eval))) {
m_td.history.update_correction_history(pos, depth, best_value - ss->static_eval);
m_td.history.update_correction_history(pos, depth, best_value - ss->static_eval, ply,
ss);
}
}

Expand Down Expand Up @@ -1166,7 +1179,7 @@ Value Worker::quiesce(const Position& pos, Stack* ss, Value alpha, Value beta, i
Value raw_eval = -VALUE_INF;
Value static_eval = -VALUE_INF;
if (!is_in_check) {
correction = m_td.history.get_correction(pos);
correction = m_td.history.get_correction(pos, ply, ss);
raw_eval = tt_data && !is_decisive_score(tt_data->eval) ? tt_data->eval : evaluate(pos);
static_eval = adj_shuffle(pos, raw_eval) + correction;

Expand Down Expand Up @@ -1204,6 +1217,9 @@ Value Worker::quiesce(const Position& pos, Stack* ss, Value alpha, Value beta, i

// Do move
ss->cont_hist_entry = &m_td.history.get_cont_hist_entry(pos, m);
ss->move = m;
ss->moved_piece = pos.piece_at(m.from());
ss->cont_corr_entry = &m_td.history.get_cont_corr_entry(pos, m);
Position pos_after = pos.move(m, m_td.push_psqt_state(), &m_searcher.tt);
moves_searched++;

Expand All @@ -1220,6 +1236,9 @@ Value Worker::quiesce(const Position& pos, Stack* ss, Value alpha, Value beta, i
repetition_info.pop();
m_td.pop_psqt_state();
ss->cont_hist_entry = nullptr;
ss->move = Move::none();
ss->moved_piece = PieceType::None;
ss->cont_corr_entry = nullptr;

if (m_stopped) {
return 0;
Expand Down
3 changes: 3 additions & 0 deletions src/search.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,9 @@ struct Stack {
Move killer = Move::none();
Move excluded_move;
ContHistEntry* cont_hist_entry = nullptr;
Move move = Move::none();
PieceType moved_piece = PieceType::None;
ContCorrEntry* cont_corr_entry = nullptr;
i32 fail_high_count = 0;
PV pv;
};
Expand Down
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