constexpr int SkipPhase[] = { 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7 };
// Razor and futility margins
- constexpr int RazorMargin[] = {0, 590, 604};
+ constexpr int RazorMargin = 600;
Value futility_margin(Depth d, bool improving) {
return Value((175 - 50 * improving) * d / ONE_PLY);
}
// History and stats update bonus, based on depth
int stat_bonus(Depth depth) {
int d = depth / ONE_PLY;
- return d > 17 ? 0 : 33 * d * d + 66 * d - 66;
+ return d > 17 ? 0 : 29 * d * d + 138 * d - 134;
}
// Skill structure is used to implement strength limit
Value minScore = this->rootMoves[0].score;
// Find out minimum score and reset votes for moves which can be voted
- for (Thread* th: Threads){
+ for (Thread* th: Threads)
+ {
minScore = std::min(minScore, th->rootMoves[0].score);
votes[th->rootMoves[0].pv[0]] = 0;
}
// Vote according to score and depth
for (Thread* th : Threads)
- votes[th->rootMoves[0].pv[0]] += int(th->rootMoves[0].score - minScore) + int(th->completedDepth);
+ votes[th->rootMoves[0].pv[0]] += int(th->rootMoves[0].score - minScore)
+ + int(th->completedDepth);
// Select best thread
int bestVote = votes[this->rootMoves[0].pv[0]];
- for (Thread* th : Threads){
- if (votes[th->rootMoves[0].pv[0]] > bestVote){
- bestVote = votes[th->rootMoves[0].pv[0]];
- bestThread = th;
+ for (Thread* th : Threads)
+ {
+ if (votes[th->rootMoves[0].pv[0]] > bestVote)
+ {
+ bestVote = votes[th->rootMoves[0].pv[0]];
+ bestThread = th;
}
}
}
-
previousScore = bestThread->rootMoves[0].score;
// Send again PV info if we have a new best thread
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
{
// Never assume anything on values stored in TT
if ((ss->staticEval = eval = tte->eval()) == VALUE_NONE)
- eval = ss->staticEval = evaluate(pos);
+ eval = ss->staticEval = 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)->currentMove != MOVE_NULL ? evaluate(pos) - 10 * ((ss-1)->statScore > 0)
: -(ss-1)->staticEval + 2 * Eval::Tempo;
tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE,
}
// Step 7. Razoring (~2 Elo)
- if ( !PvNode
- && depth < 3 * ONE_PLY
- && eval <= alpha - RazorMargin[depth / ONE_PLY])
- {
- Value ralpha = alpha - (depth >= 2 * ONE_PLY) * RazorMargin[depth / ONE_PLY];
- Value v = qsearch<NonPV>(pos, ss, ralpha, ralpha+1);
- if (depth < 2 * ONE_PLY || v <= ralpha)
- return v;
- }
+ if ( depth < 2 * ONE_PLY
+ && eval <= alpha - RazorMargin)
+ return qsearch<NT>(pos, ss, alpha, beta);
improving = ss->staticEval >= (ss-2)->staticEval
|| (ss-2)->staticEval == VALUE_NONE;
// Step 9. Null move search with verification search (~40 Elo)
if ( !PvNode
&& (ss-1)->currentMove != MOVE_NULL
- && (ss-1)->statScore < 22500
+ && (ss-1)->statScore < 23200
&& eval >= beta
&& ss->staticEval >= beta - 36 * depth / ONE_PLY + 225
&& !excludedMove
{
Depth r = reduction<PvNode>(improving, depth, moveCount);
- if (captureOrPromotion) // (~5 Elo)
- {
- // Decrease reduction by comparing opponent's stat score
- if ((ss-1)->statScore < 0)
- r -= ONE_PLY;
- }
- else
- {
- // Decrease reduction if opponent's move count is high (~5 Elo)
- if ((ss-1)->moveCount > 15)
- r -= ONE_PLY;
+ // Decrease reduction if opponent's move count is high (~10 Elo)
+ if ((ss-1)->moveCount > 15)
+ r -= ONE_PLY;
+ if (!captureOrPromotion)
+ {
// Decrease reduction for exact PV nodes (~0 Elo)
if (pvExact)
r -= ONE_PLY;