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Update Elo estimates for terms in search

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based on 25k games per term, using the UHO_XXL_+0.90_+1.19.epd book, at STC.

More detailed information in the PR.

closes https://github.com/official-stockfish/Stockfish/pull/4294

No functional change
This commit is contained in:
FauziAkram 2022-12-20 22:54:12 +03:00 • committed by Joost VandeVondele
parent c620886181
commit b2bd8699ec
1 changed files with 24 additions and 24 deletions
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48
src/search.cpp
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@ -633,16 +633,16 @@ namespace {
&& ttValue != VALUE_NONE // Possible in case of TT access race
&& (tte->bound() & (ttValue >= beta ? BOUND_LOWER : BOUND_UPPER)))
{
// If ttMove is quiet, update move sorting heuristics on TT hit (~1 Elo)
// If ttMove is quiet, update move sorting heuristics on TT hit (~2 Elo)
if (ttMove)
{
if (ttValue >= beta)
{
// Bonus for a quiet ttMove that fails high (~3 Elo)
// Bonus for a quiet ttMove that fails high (~2 Elo)
if (!ttCapture)
update_quiet_stats(pos, ss, ttMove, stat_bonus(depth));
// Extra penalty for early quiet moves of the previous ply (~0 Elo)
// Extra penalty for early quiet moves of the previous ply (~0 Elo on STC, ~2 Elo on LTC)
if ((ss-1)->moveCount <= 2 && !priorCapture)
update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1));
}
@ -734,7 +734,7 @@ namespace {
else // Fall back to (semi)classical complexity for TT hits, the NNUE complexity is lost
complexity = abs(ss->staticEval - pos.psq_eg_stm());
// ttValue can be used as a better position evaluation (~4 Elo)
// ttValue can be used as a better position evaluation (~7 Elo)
if ( ttValue != VALUE_NONE
&& (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER)))
eval = ttValue;
@ -750,7 +750,7 @@ namespace {
thisThread->complexityAverage.update(complexity);
// Use static evaluation difference to improve quiet move ordering (~3 Elo)
// Use static evaluation difference to improve quiet move ordering (~4 Elo)
if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture)
{
int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1914, 1914);
@ -766,7 +766,7 @@ namespace {
: 168;
improving = improvement > 0;
// Step 7. Razoring.
// Step 7. Razoring (~1 Elo).
// If eval is really low check with qsearch if it can exceed alpha, if it can't,
// return a fail low.
if (eval < alpha - 369 - 254 * depth * depth)
@ -776,7 +776,7 @@ namespace {
return value;
}
// Step 8. Futility pruning: child node (~25 Elo).
// Step 8. Futility pruning: child node (~40 Elo).
// The depth condition is important for mate finding.
if ( !ss->ttPv
&& depth < 8
@ -785,7 +785,7 @@ namespace {
&& eval < 28031) // larger than VALUE_KNOWN_WIN, but smaller than TB wins
return eval;
// Step 9. Null move search with verification search (~22 Elo)
// Step 9. Null move search with verification search (~35 Elo)
if ( !PvNode
&& (ss-1)->currentMove != MOVE_NULL
&& (ss-1)->statScore < 17139
@ -837,7 +837,7 @@ namespace {
probCutBeta = beta + 191 - 54 * improving;
// Step 10. ProbCut (~4 Elo)
// Step 10. ProbCut (~10 Elo)
// If we have a good enough capture and a reduced search returns a value
// much above beta, we can (almost) safely prune the previous move.
if ( !PvNode
@ -888,7 +888,7 @@ namespace {
}
// Step 11. If the position is not in TT, decrease depth by 3.
// Use qsearch if depth is equal or below zero (~4 Elo)
// Use qsearch if depth is equal or below zero (~9 Elo)
if ( PvNode
&& !ttMove)
depth -= 3;
@ -903,7 +903,7 @@ namespace {
moves_loop: // When in check, search starts here
// Step 12. A small Probcut idea, when we are in check (~0 Elo)
// Step 12. A small Probcut idea, when we are in check (~4 Elo)
probCutBeta = beta + 417;
if ( ss->inCheck
&& !PvNode
@ -980,12 +980,12 @@ moves_loop: // When in check, search starts here
Value delta = beta - alpha;
// Step 14. Pruning at shallow depth (~98 Elo). Depth conditions are important for mate finding.
// Step 14. Pruning at shallow depth (~120 Elo). Depth conditions are important for mate finding.
if ( !rootNode
&& pos.non_pawn_material(us)
&& bestValue > VALUE_TB_LOSS_IN_MAX_PLY)
{
// Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~7 Elo)
// Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~8 Elo)
moveCountPruning = moveCount >= futility_move_count(improving, depth);
// Reduced depth of the next LMR search
@ -994,7 +994,7 @@ moves_loop: // When in check, search starts here
if ( capture
|| givesCheck)
{
// Futility pruning for captures (~0 Elo)
// Futility pruning for captures (~2 Elo)
if ( !givesCheck
&& !PvNode
&& lmrDepth < 7
@ -1003,7 +1003,7 @@ moves_loop: // When in check, search starts here
+ captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 6 < alpha)
continue;
// SEE based pruning (~9 Elo)
// SEE based pruning (~11 Elo)
if (!pos.see_ge(move, Value(-222) * depth))
continue;
}
@ -1020,23 +1020,23 @@ moves_loop: // When in check, search starts here
history += 2 * thisThread->mainHistory[us][from_to(move)];
// Futility pruning: parent node (~9 Elo)
// Futility pruning: parent node (~13 Elo)
if ( !ss->inCheck
&& lmrDepth < 13
&& ss->staticEval + 106 + 145 * lmrDepth + history / 52 <= alpha)
continue;
// Prune moves with negative SEE (~3 Elo)
// Prune moves with negative SEE (~4 Elo)
if (!pos.see_ge(move, Value(-24 * lmrDepth * lmrDepth - 15 * lmrDepth)))
continue;
}
}
// Step 15. Extensions (~66 Elo)
// Step 15. Extensions (~100 Elo)
// We take care to not overdo to avoid search getting stuck.
if (ss->ply < thisThread->rootDepth * 2)
{
// Singular extension search (~58 Elo). If all moves but one fail low on a
// Singular extension search (~94 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 all the other moves but the ttMove and if the
@ -1095,7 +1095,7 @@ moves_loop: // When in check, search starts here
&& abs(ss->staticEval) > 82)
extension = 1;
// Quiet ttMove extensions (~0 Elo)
// Quiet ttMove extensions (~1 Elo)
else if ( PvNode
&& move == ttMove
&& move == ss->killers[0]
@ -1166,7 +1166,7 @@ moves_loop: // When in check, search starts here
// Decrease/increase reduction for moves with a good/bad history (~30 Elo)
r -= ss->statScore / (13000 + 4152 * (depth > 7 && depth < 19));
// Step 17. Late moves reduction / extension (LMR, ~98 Elo)
// Step 17. Late moves reduction / extension (LMR, ~117 Elo)
// We use various heuristics for the sons of a node after the first son has
// been searched. In general we would like to reduce them, but there are many
// cases where we extend a son if it has good chances to be "interesting".
@ -1462,7 +1462,7 @@ moves_loop: // When in check, search starts here
if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE)
ss->staticEval = bestValue = evaluate(pos);
// ttValue can be used as a better position evaluation (~7 Elo)
// ttValue can be used as a better position evaluation (~13 Elo)
if ( ttValue != VALUE_NONE
&& (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER)))
bestValue = ttValue;
@ -1520,7 +1520,7 @@ moves_loop: // When in check, search starts here
moveCount++;
// Futility pruning and moveCount pruning (~5 Elo)
// Futility pruning and moveCount pruning (~10 Elo)
if ( bestValue > VALUE_TB_LOSS_IN_MAX_PLY
&& !givesCheck
&& to_sq(move) != prevSq
@ -1559,7 +1559,7 @@ moves_loop: // When in check, search starts here
[pos.moved_piece(move)]
[to_sq(move)];
// Continuation history based pruning (~2 Elo)
// Continuation history based pruning (~3 Elo)
if ( !capture
&& bestValue > VALUE_TB_LOSS_IN_MAX_PLY
&& (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < 0