bestPreviousScore = bestThread->rootMoves[0].score;
bestPreviousAverageScore = bestThread->rootMoves[0].averageScore;
+ for (Thread* th : Threads)
+ th->previousDepth = bestThread->completedDepth;
+
// Send again PV info if we have a new best thread
if (bestThread != this)
sync_cout << UCI::pv(bestThread->rootPos, bestThread->completedDepth, -VALUE_INFINITE, VALUE_INFINITE) << sync_endl;
// If the bestMove is stable over several iterations, reduce time accordingly
timeReduction = lastBestMoveDepth + 10 < completedDepth ? 1.63 : 0.73;
double reduction = (1.56 + mainThread->previousTimeReduction) / (2.20 * timeReduction);
- double bestMoveInstability = 1.073 + std::max(1.0, 2.25 - 9.9 / rootDepth)
- * totBestMoveChanges / Threads.size();
+ double bestMoveInstability = 1 + 1.7 * totBestMoveChanges / Threads.size();
int complexity = mainThread->complexityAverage.value();
double complexPosition = std::clamp(1.0 + (complexity - 326) / 1618.1, 0.5, 1.5);
Depth extension, newDepth;
Value bestValue, value, ttValue, eval, maxValue, probCutBeta;
bool givesCheck, improving, didLMR, priorCapture;
- bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture;
+ bool capture, doFullDepthSearch, moveCountPruning, ttCapture;
Piece movedPiece;
- int moveCount, captureCount, quietCount, bestMoveCount, improvement, complexity;
+ int moveCount, captureCount, quietCount, improvement, complexity;
// Step 1. Initialize node
Thread* thisThread = pos.this_thread();
+ thisThread->depth = depth;
ss->inCheck = pos.checkers();
priorCapture = pos.captured_piece();
Color us = pos.side_to_move();
- moveCount = bestMoveCount = captureCount = quietCount = ss->moveCount = 0;
+ moveCount = captureCount = quietCount = ss->moveCount = 0;
bestValue = -VALUE_INFINITE;
maxValue = VALUE_INFINITE;
(ss+1)->ttPv = false;
(ss+1)->excludedMove = bestMove = MOVE_NONE;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
+ (ss+2)->cutoffCnt = 0;
ss->doubleExtensions = (ss-1)->doubleExtensions;
- ss->depth = depth;
Square prevSq = to_sq((ss-1)->currentMove);
// Initialize statScore to zero for the grandchildren of the current position.
ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0]
: ss->ttHit ? tte->move() : MOVE_NONE;
- ttCapture = ttMove && pos.capture_or_promotion(ttMove);
+ ttCapture = ttMove && pos.capture(ttMove);
if (!excludedMove)
ss->ttPv = PvNode || (ss->ttHit && tte->is_pv());
while ((move = mp.next_move()) != MOVE_NONE)
if (move != excludedMove && pos.legal(move))
{
- assert(pos.capture_or_promotion(move));
-
- captureOrPromotion = true;
+ assert(pos.capture(move) || promotion_type(move) == QUEEN);
ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
- [captureOrPromotion]
+ [true]
[pos.moved_piece(move)]
[to_sq(move)];
(ss+1)->pv = nullptr;
extension = 0;
- captureOrPromotion = pos.capture_or_promotion(move);
+ capture = pos.capture(move);
movedPiece = pos.moved_piece(move);
givesCheck = pos.gives_check(move);
// Reduced depth of the next LMR search
int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount, delta, thisThread->rootDelta), 0);
- if ( captureOrPromotion
+ if ( capture
|| givesCheck)
{
// Futility pruning for captures (~0 Elo)
// a reduced search on all the other moves but the ttMove and if the
// result is lower than ttValue minus a margin, then we will extend the ttMove.
if ( !rootNode
- && depth >= 4 + 2 * (PvNode && tte->is_pv())
+ && depth >= 4 - (thisThread->previousDepth > 27) + 2 * (PvNode && tte->is_pv())
&& move == ttMove
&& !excludedMove // Avoid recursive singular search
/* && ttValue != VALUE_NONE Already implicit in the next condition */
// If the eval of ttMove is greater than beta, we reduce it (negative extension)
else if (ttValue >= beta)
extension = -2;
+
+ // If the eval of ttMove is less than alpha and value, we reduce it (negative extension)
+ else if (ttValue <= alpha && ttValue <= value)
+ extension = -1;
}
// Check extensions (~1 Elo)
// Update the current move (this must be done after singular extension search)
ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
- [captureOrPromotion]
+ [capture]
[movedPiece]
[to_sq(move)];
if ( depth >= 2
&& moveCount > 1 + (PvNode && ss->ply <= 1)
&& ( !ss->ttPv
- || !captureOrPromotion
+ || !capture
|| (cutNode && (ss-1)->moveCount > 1)))
{
Depth r = reduction(improving, depth, moveCount, delta, thisThread->rootDelta);
- // Decrease reduction at some PvNodes (~2 Elo)
- if ( PvNode
- && bestMoveCount <= 3)
- r--;
-
// Decrease reduction if position is or has been on the PV
// and node is not likely to fail low. (~3 Elo)
if ( ss->ttPv
if (PvNode && !ss->inCheck && abs(ss->staticEval - bestValue) > 250)
r--;
+ // Decrease reduction for PvNodes based on depth
+ if (PvNode)
+ r -= 1 + 15 / ( 3 + depth );
+
+ // Increase reduction if next ply has a lot of fail high else reset count to 0
+ if ((ss+1)->cutoffCnt > 3 && !PvNode)
+ r++;
+
ss->statScore = thisThread->mainHistory[us][from_to(move)]
+ (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
// deeper than the first move (this may lead to hidden double extensions).
int deeper = r >= -1 ? 0
: moveCount <= 4 ? 2
- : PvNode && depth > 4 ? 1
+ : PvNode ? 1
: cutNode && moveCount <= 8 ? 1
: 0;
int bonus = value > alpha ? stat_bonus(newDepth)
: -stat_bonus(newDepth);
- if (captureOrPromotion)
+ if (capture)
bonus /= 6;
update_continuation_histories(ss, movedPiece, to_sq(move), bonus);
if (PvNode && value < beta) // Update alpha! Always alpha < beta
{
alpha = value;
- bestMoveCount++;
+
+ // Reduce other moves if we have found at least one score improvement
+ if ( depth > 2
+ && depth < 7
+ && beta < VALUE_KNOWN_WIN
+ && alpha > -VALUE_KNOWN_WIN)
+ depth -= 1;
+
+ assert(depth > 0);
}
else
{
+ ss->cutoffCnt++;
assert(value >= beta); // Fail high
break;
}
}
}
+ else
+ ss->cutoffCnt = 0;
+
// If the move is worse than some previously searched move, remember it to update its stats later
if (move != bestMove)
{
- if (captureOrPromotion && captureCount < 32)
+ if (capture && captureCount < 32)
capturesSearched[captureCount++] = move;
- else if (!captureOrPromotion && quietCount < 64)
+ else if (!capture && quietCount < 64)
quietsSearched[quietCount++] = move;
}
}
// opponent move is probably good and the new position is added to the search tree.
if (bestValue <= alpha)
ss->ttPv = ss->ttPv || ((ss-1)->ttPv && depth > 3);
- // Otherwise, a counter move has been found and if the position is the last leaf
- // in the search tree, remove the position from the search tree.
- else if (depth > 3)
- ss->ttPv = ss->ttPv && (ss+1)->ttPv;
// Write gathered information in transposition table
if (!excludedMove && !(rootNode && thisThread->pvIdx))
Move ttMove, move, bestMove;
Depth ttDepth;
Value bestValue, value, ttValue, futilityValue, futilityBase;
- bool pvHit, givesCheck, captureOrPromotion;
+ bool pvHit, givesCheck, capture;
int moveCount;
if (PvNode)
continue;
givesCheck = pos.gives_check(move);
- captureOrPromotion = pos.capture_or_promotion(move);
+ capture = pos.capture(move);
moveCount++;
ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
- [captureOrPromotion]
+ [capture]
[pos.moved_piece(move)]
[to_sq(move)];
// Continuation history based pruning (~2 Elo)
- if ( !captureOrPromotion
+ if ( !capture
&& bestValue > VALUE_TB_LOSS_IN_MAX_PLY
&& (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold
&& (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold)
// movecount pruning for quiet check evasions
if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY
&& quietCheckEvasions > 1
- && !captureOrPromotion
+ && !capture
&& ss->inCheck)
continue;
- quietCheckEvasions += !captureOrPromotion && ss->inCheck;
+ quietCheckEvasions += !capture && ss->inCheck;
// Make and search the move
pos.do_move(move, st, givesCheck);
bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus
: stat_bonus(depth); // smaller bonus
- if (!pos.capture_or_promotion(bestMove))
+ if (!pos.capture(bestMove))
{
// Increase stats for the best move in case it was a quiet move
update_quiet_stats(pos, ss, bestMove, bonus2);
projects / stockfish / blobdiff