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) : VALUE_DRAW;
+ return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) - 10 * ((ss-1)->statScore > 0)
+ : 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 = pureStaticEval = eval = 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);
+ if ((ss->staticEval = pureStaticEval = eval = tte->eval()) == VALUE_NONE)
+ eval = ss->staticEval = (pureStaticEval = evaluate(pos)) - 10 * ((ss-1)->statScore > 0);
// Can ttValue be used as a better position evaluation?
if ( ttValue != VALUE_NONE
}
else
{
- ss->staticEval = eval =
- (ss-1)->currentMove != MOVE_NULL ? evaluate(pos)
- : -(ss-1)->staticEval + 2 * Eval::Tempo;
+ int p = (ss-1)->statScore;
+ int malus = p > 0 ? (p + 5000) / 1024 :
+ p < 0 ? (p - 5000) / 1024 : 0;
- tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE,
- ss->staticEval);
+ ss->staticEval = eval = (ss-1)->currentMove != MOVE_NULL ? (pureStaticEval = evaluate(pos)) - malus
+ : (pureStaticEval = -(ss-1)->staticEval + 2 * Eval::Tempo);
+
+ tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, pureStaticEval);
}
// Step 7. Razoring (~2 Elo)
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);