The idea is that chances are the tt-move is best and will be difficult to raise alpha when playing a quiet move.
STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 7582 W: 1415 L: 1259 D: 4908
LTC:
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 59553 W: 7885 L: 7573 D: 44095
Bench:
5725676
Closes #1147
Depth extension, newDepth;
Value bestValue, value, ttValue, eval;
bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
Depth extension, newDepth;
Value bestValue, value, ttValue, eval;
bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
- bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets;
+ bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture;
Piece moved_piece;
int moveCount, quietCount;
Piece moved_piece;
int moveCount, quietCount;
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;
skipQuiets = false;
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;
skipQuiets = false;
// Step 11. Loop through moves
// Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
// Step 11. Loop through moves
// Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
ss->moveCount = --moveCount;
continue;
}
ss->moveCount = --moveCount;
continue;
}
+
+ if (move == ttMove && captureOrPromotion)
+ ttCapture = true;
// Update the current move (this must be done after singular extension search)
ss->currentMove = move;
// Update the current move (this must be done after singular extension search)
ss->currentMove = move;
r -= r ? ONE_PLY : DEPTH_ZERO;
else
{
r -= r ? ONE_PLY : DEPTH_ZERO;
else
{
+
+ // Increase reduction if ttMove is a capture
+ if (ttCapture)
+ r += ONE_PLY;
+
// Increase reduction for cut nodes
if (cutNode)
r += 2 * ONE_PLY;
// Increase reduction for cut nodes
if (cutNode)
r += 2 * ONE_PLY;