Key posKey;
Move ttMove, move, excludedMove, bestMove;
Depth extension, newDepth;
- Value bestValue, value, ttValue, eval, maxValue;
+ Value bestValue, value, ttValue, eval, maxValue, pureStaticEval;
bool ttHit, inCheck, givesCheck, improving;
bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact;
Piece movedPiece;
if ( Threads.stop.load(std::memory_order_relaxed)
|| pos.is_draw(ss->ply)
|| ss->ply >= MAX_PLY)
- return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) - 10 * ((ss-1)->statScore > 0)
- : VALUE_DRAW;
+ return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) : VALUE_DRAW;
// Step 3. Mate distance pruning. Even if we mate at the next move our score
// would be at best mate_in(ss->ply+1), but if alpha is already bigger because
// Step 6. Static evaluation of the position
if (inCheck)
{
- ss->staticEval = eval = VALUE_NONE;
+ ss->staticEval = eval = pureStaticEval = VALUE_NONE;
improving = false;
goto moves_loop; // Skip early pruning when in check
}
else if (ttHit)
{
// Never assume anything on values stored in TT
- if ((ss->staticEval = eval = tte->eval()) == VALUE_NONE)
- eval = ss->staticEval = evaluate(pos) - 10 * ((ss-1)->statScore > 0);
+ ss->staticEval = eval = pureStaticEval = tte->eval();
+ if (eval == VALUE_NONE)
+ ss->staticEval = eval = pureStaticEval = evaluate(pos);
// Can ttValue be used as a better position evaluation?
if ( ttValue != VALUE_NONE
}
else
{
- int p = (ss-1)->statScore;
- int malus = p > 0 ? (p + 5000) / 1024 :
- p < 0 ? (p - 5000) / 1024 : 0;
+ if ((ss-1)->currentMove != MOVE_NULL)
+ {
+ int p = (ss-1)->statScore;
+ int bonus = p > 0 ? (-p - 2500) / 512 :
+ p < 0 ? (-p + 2500) / 512 : 0;
- ss->staticEval = eval = (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) - malus
- : -(ss-1)->staticEval + 2 * Eval::Tempo;
+ pureStaticEval = evaluate(pos);
+ ss->staticEval = eval = pureStaticEval + bonus;
+ }
+ else
+ ss->staticEval = eval = pureStaticEval = -(ss-1)->staticEval + 2 * Eval::Tempo;
- tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, ss->staticEval);
+ tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, pureStaticEval);
}
// Step 7. Razoring (~2 Elo)
&& (ss-1)->currentMove != MOVE_NULL
&& (ss-1)->statScore < 23200
&& eval >= beta
- && ss->staticEval >= beta - 36 * depth / ONE_PLY + 225
+ && pureStaticEval >= beta - 36 * depth / ONE_PLY + 225
&& !excludedMove
&& pos.non_pawn_material(us)
&& (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
assert(eval - beta >= 0);
// Null move dynamic reduction based on depth and value
- Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
+ Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min(int(eval - beta) / 200, 3)) * ONE_PLY;
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[NO_PIECE][0];
while ( (move = mp.next_move()) != MOVE_NONE
&& probCutCount < 3)
- if (pos.legal(move))
+ if (move != excludedMove && pos.legal(move))
{
probCutCount++;
// Singular extension search (~60 Elo). If all moves but one fail low on a
// search of (alpha-s, beta-s), and just one fails high on (alpha, beta),
// then that move is singular and should be extended. To verify this we do
- // a reduced search on on all the other moves but the ttMove and if the
+ // 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 ( depth >= 8 * ONE_PLY
&& move == ttMove
tte->save(posKey, value_to_tt(bestValue, ss->ply),
bestValue >= beta ? BOUND_LOWER :
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
- depth, bestMove, ss->staticEval);
+ depth, bestMove, pureStaticEval);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);