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Merge commit 'a2a7edf4c8fa145667135bf1bc7f4f67016f7608' into cluster

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This is the last commit before there are more conflicts.
This commit is contained in:
Steinar H. Gunderson
2025-12-24 16:19:29 +01:00
parent bc81aa0911 a2a7edf4c8
commit 784db2cbed
14 changed files with 396 additions and 273 deletions
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src/search.cpp
+25 -20
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@@ -162,7 +162,7 @@ void Search::Worker::start_searching() {
}
main_manager()->tm.init(limits, rootPos.side_to_move(), rootPos.game_ply(), options,
main_manager()->originalPly);
main_manager()->originalTimeAdjust);
tt.new_search();
if (rootMoves.empty())
@@ -598,11 +598,12 @@ Value Search::Worker::search(
Key posKey;
Move ttMove, move, excludedMove, bestMove;
Depth extension, newDepth;
Value bestValue, value, ttValue, eval, maxValue, probCutBeta;
Value bestValue, value, ttValue, eval, maxValue, probCutBeta, singularValue;
bool givesCheck, improving, priorCapture, opponentWorsening;
bool capture, moveCountPruning, ttCapture;
Piece movedPiece;
int moveCount, captureCount, quietCount;
Bound singularBound;
// Step 1. Initialize node
Worker* thisThread = this;
@@ -667,7 +668,7 @@ Value Search::Worker::search(
ss->ttPv = PvNode || (ss->ttHit && tte->is_pv());
// At non-PV nodes we check for an early TT cutoff
if (!PvNode && !excludedMove && tte->depth() > depth
if (!PvNode && !excludedMove && tte->depth() > depth - (ttValue <= beta)
&& ttValue != VALUE_NONE // Possible in case of TT access race or if !ttHit
&& (tte->bound() & (ttValue >= beta ? BOUND_LOWER : BOUND_UPPER)))
{
@@ -973,6 +974,8 @@ moves_loop: // When in check, search starts here
value = bestValue;
moveCountPruning = false;
singularValue = VALUE_INFINITE;
singularBound = BOUND_NONE;
// Step 13. Loop through all pseudo-legal moves until no moves remain
// or a beta cutoff occurs.
@@ -1022,7 +1025,9 @@ moves_loop: // When in check, search starts here
if (!rootNode && pos.non_pawn_material(us) && bestValue > VALUE_TB_LOSS_IN_MAX_PLY)
{
// Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~8 Elo)
moveCountPruning = moveCount >= futility_move_count(improving, depth);
moveCountPruning =
moveCount >= futility_move_count(improving, depth)
- (singularBound == BOUND_UPPER && singularValue < alpha - 50);
// Reduced depth of the next LMR search
int lmrDepth = newDepth - r;
@@ -1108,19 +1113,18 @@ moves_loop: // When in check, search starts here
Depth singularDepth = newDepth / 2;
ss->excludedMove = move;
value =
value = singularValue =
search<NonPV>(pos, ss, singularBeta - 1, singularBeta, singularDepth, cutNode);
singularBound = singularValue >= singularBeta ? BOUND_LOWER : BOUND_UPPER;
ss->excludedMove = Move::none();
if (value < singularBeta)
{
int doubleMargin = 304 * PvNode - 203 * !ttCapture;
int tripleMargin = 117 + 259 * PvNode - 296 * !ttCapture + 97 * ss->ttPv;
int quadMargin = 486 + 343 * PvNode - 273 * !ttCapture + 232 * ss->ttPv;
extension = 1 + (value < singularBeta - doubleMargin)
+ (value < singularBeta - tripleMargin)
+ (value < singularBeta - quadMargin);
+ (value < singularBeta - tripleMargin);
depth += ((!PvNode) && (depth < 16));
}
@@ -1201,17 +1205,17 @@ moves_loop: // When in check, search starts here
if ((ss + 1)->cutoffCnt > 3)
r++;
// Set reduction to 0 for first picked move (ttMove) (~2 Elo)
// Nullifies all previous reduction adjustments to ttMove and leaves only history to do them
// For first picked move (ttMove) reduce reduction
// but never allow it to go below 0 (~3 Elo)
else if (move == ttMove)
r = 0;
r = std::max(0, r - 2);
ss->statScore = 2 * thisThread->mainHistory[us][move.from_to()]
+ (*contHist[0])[movedPiece][move.to_sq()]
+ (*contHist[1])[movedPiece][move.to_sq()] - 5169;
// Decrease/increase reduction for moves with a good/bad history (~8 Elo)
r -= ss->statScore / (12219 - std::min(depth, 13) * 120);
r -= ss->statScore / 11049;
// Step 17. Late moves reduction / extension (LMR, ~117 Elo)
if (depth >= 2 && moveCount > 1 + rootNode)
@@ -1341,7 +1345,7 @@ moves_loop: // When in check, search starts here
if (value >= beta)
{
ss->cutoffCnt += 1 + !ttMove;
ss->cutoffCnt += 1 + !ttMove - (extension >= 2);
assert(value >= beta); // Fail high
break;
}
@@ -1391,18 +1395,19 @@ moves_loop: // When in check, search starts here
// Bonus for prior countermove that caused the fail low
else if (!priorCapture && prevSq != SQ_NONE)
{
int bonus = (depth > 4) + (depth > 5) + (PvNode || cutNode) + ((ss - 1)->statScore < -14144)
+ ((ss - 1)->moveCount > 9) + (!ss->inCheck && bestValue <= ss->staticEval - 115)
+ (!(ss - 1)->inCheck && bestValue <= -(ss - 1)->staticEval - 81);
int bonus = (116 * (depth > 5) + 115 * (PvNode || cutNode)
+ 186 * ((ss - 1)->statScore < -14144) + 121 * ((ss - 1)->moveCount > 9)
+ 64 * (!ss->inCheck && bestValue <= ss->staticEval - 115)
+ 137 * (!(ss - 1)->inCheck && bestValue <= -(ss - 1)->staticEval - 81));
update_continuation_histories(ss - 1, pos.piece_on(prevSq), prevSq,
stat_bonus(depth) * bonus);
stat_bonus(depth) * bonus / 100);
thisThread->mainHistory[~us][((ss - 1)->currentMove).from_to()]
<< stat_bonus(depth) * bonus / 2;
<< stat_bonus(depth) * bonus / 200;
if (type_of(pos.piece_on(prevSq)) != PAWN && ((ss - 1)->currentMove).type_of() != PROMOTION)
thisThread->pawnHistory[pawn_structure_index(pos)][pos.piece_on(prevSq)][prevSq]
<< stat_bonus(depth) * bonus * 4;
<< stat_bonus(depth) * bonus / 25;
}
if (PvNode)
@@ -1536,7 +1541,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos);
// ttValue can be used as a better position evaluation (~13 Elo)
if (ttValue != VALUE_NONE
if (std::abs(ttValue) < VALUE_TB_WIN_IN_MAX_PLY
&& (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER)))
bestValue = ttValue;
}