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Merge commit '3502c8ae426506453ca64e87e48d962b327c2356' into cluster

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This commit is contained in:
Steinar H. Gunderson
2025-12-24 15:12:37 +01:00
parent ba47c8eeeb 3502c8ae42
commit 5f5f991780
15 changed files with 411 additions and 126 deletions
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src/search.cpp
+45 -36
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@@ -34,6 +34,8 @@
#include "misc.h"
#include "movegen.h"
#include "movepick.h"
#include "nnue/network.h"
#include "nnue/nnue_accumulator.h"
#include "nnue/nnue_common.h"
#include "nnue/nnue_misc.h"
#include "position.h"
@@ -53,14 +55,14 @@ using namespace Search;
namespace {
static constexpr double EvalLevel[10] = {1.043, 1.017, 0.952, 1.009, 0.971,
1.002, 0.992, 0.947, 1.046, 1.001};
static constexpr double EvalLevel[10] = {0.981, 0.956, 0.895, 0.949, 0.913,
0.942, 0.933, 0.890, 0.984, 0.941};
// Futility margin
Value futility_margin(Depth d, bool noTtCutNode, bool improving, bool oppWorsening) {
Value futilityMult = 118 - 44 * noTtCutNode;
Value futilityMult = 118 - 45 * noTtCutNode;
Value improvingDeduction = 52 * improving * futilityMult / 32;
Value worseningDeduction = (310 + 48 * improving) * oppWorsening * futilityMult / 1024;
Value worseningDeduction = (316 + 48 * improving) * oppWorsening * futilityMult / 1024;
return futilityMult * d - improvingDeduction - worseningDeduction;
}
@@ -77,10 +79,10 @@ Value to_corrected_static_eval(Value v, const Worker& w, const Position& pos) {
}
// History and stats update bonus, based on depth
int stat_bonus(Depth d) { return std::clamp(211 * d - 315, 0, 1291); }
int stat_bonus(Depth d) { return std::clamp(214 * d - 318, 16, 1304); }
// History and stats update malus, based on depth
int stat_malus(Depth d) { return (d < 4 ? 572 * d - 285 : 1372); }
int stat_malus(Depth d) { return (d < 4 ? 572 * d - 284 : 1355); }
// Add a small random component to draw evaluations to avoid 3-fold blindness
Value value_draw(size_t nodes) { return VALUE_DRAW - 1 + Value(nodes & 0x2); }
@@ -139,11 +141,16 @@ Search::Worker::Worker(SharedState& sharedState,
options(sharedState.options),
threads(sharedState.threads),
tt(sharedState.tt),
networks(sharedState.networks) {
networks(sharedState.networks),
refreshTable(networks) {
clear();
}
void Search::Worker::start_searching() {
// Initialize accumulator refresh entries
refreshTable.clear(networks);
// Non-main threads go directly to iterative_deepening()
if (!is_mainthread())
{
@@ -345,12 +352,12 @@ void Search::Worker::iterative_deepening() {
// Reset aspiration window starting size
Value avg = rootMoves[pvIdx].averageScore;
delta = 11 + avg * avg / 11254;
delta = 10 + avg * avg / 11480;
alpha = std::max(avg - delta, -VALUE_INFINITE);
beta = std::min(avg + delta, VALUE_INFINITE);
// Adjust optimism based on root move's averageScore (~4 Elo)
optimism[us] = 125 * avg / (std::abs(avg) + 91);
optimism[us] = 122 * avg / (std::abs(avg) + 92);
optimism[~us] = -optimism[us];
// Start with a small aspiration window and, in the case of a fail
@@ -487,9 +494,10 @@ void Search::Worker::iterative_deepening() {
double reduction = (1.48 + mainThread->previousTimeReduction) / (2.17 * timeReduction);
double bestMoveInstability = 1 + 1.88 * totBestMoveChanges / threads.size();
int el = std::clamp((bestValue + 750) / 150, 0, 9);
double recapture = limits.capSq == rootMoves[0].pv[0].to_sq() ? 0.955 : 1.005;
double totalTime = mainThread->tm.optimum() * fallingEval * reduction
* bestMoveInstability * EvalLevel[el];
* bestMoveInstability * EvalLevel[el] * recapture;
// Cap used time in case of a single legal move for a better viewer experience
if (rootMoves.size() == 1)
@@ -612,7 +620,7 @@ Value Search::Worker::search(
if (threads.stop.load(std::memory_order_relaxed) || pos.is_draw(ss->ply)
|| ss->ply >= MAX_PLY)
return (ss->ply >= MAX_PLY && !ss->inCheck)
? evaluate(networks, pos, thisThread->optimism[us])
? evaluate(networks, pos, refreshTable, thisThread->optimism[us])
: value_draw(thisThread->nodes);
// Step 3. Mate distance pruning. Even if we mate at the next move our score
@@ -746,7 +754,7 @@ Value Search::Worker::search(
{
// Providing the hint that this node's accumulator will be used often
// brings significant Elo gain (~13 Elo).
Eval::NNUE::hint_common_parent_position(pos, networks);
Eval::NNUE::hint_common_parent_position(pos, networks, refreshTable);
unadjustedStaticEval = eval = ss->staticEval;
}
else if (ss->ttHit)
@@ -754,9 +762,9 @@ Value Search::Worker::search(
// Never assume anything about values stored in TT
unadjustedStaticEval = tte->eval();
if (unadjustedStaticEval == VALUE_NONE)
unadjustedStaticEval = evaluate(networks, pos, thisThread->optimism[us]);
unadjustedStaticEval = evaluate(networks, pos, refreshTable, thisThread->optimism[us]);
else if (PvNode)
Eval::NNUE::hint_common_parent_position(pos, networks);
Eval::NNUE::hint_common_parent_position(pos, networks, refreshTable);
ss->staticEval = eval = to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos);
@@ -766,7 +774,7 @@ Value Search::Worker::search(
}
else
{
unadjustedStaticEval = evaluate(networks, pos, thisThread->optimism[us]);
unadjustedStaticEval = evaluate(networks, pos, refreshTable, thisThread->optimism[us]);
ss->staticEval = eval = to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos);
// Static evaluation is saved as it was before adjustment by correction history
@@ -800,7 +808,7 @@ Value Search::Worker::search(
// If eval is really low check with qsearch if it can exceed alpha, if it can't,
// return a fail low.
// Adjust razor margin according to cutoffCnt. (~1 Elo)
if (eval < alpha - 471 - (276 - 148 * ((ss + 1)->cutoffCnt > 3)) * depth * depth)
if (eval < alpha - 471 - (275 - 148 * ((ss + 1)->cutoffCnt > 3)) * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha)
@@ -811,14 +819,14 @@ Value Search::Worker::search(
// The depth condition is important for mate finding.
if (!ss->ttPv && depth < 12
&& eval - futility_margin(depth, cutNode && !ss->ttHit, improving, opponentWorsening)
- (ss - 1)->statScore / 284
- (ss - 1)->statScore / 286
>= beta
&& eval >= beta && eval < VALUE_TB_WIN_IN_MAX_PLY && (!ttMove || ttCapture))
return beta > VALUE_TB_LOSS_IN_MAX_PLY ? (eval + beta) / 2 : eval;
// Step 9. Null move search with verification search (~35 Elo)
if (!PvNode && (ss - 1)->currentMove != Move::null() && (ss - 1)->statScore < 18001
&& eval >= beta && ss->staticEval >= beta - 21 * depth + 315 && !excludedMove
&& eval >= beta && ss->staticEval >= beta - 21 * depth + 312 && !excludedMove
&& pos.non_pawn_material(us) && ss->ply >= thisThread->nmpMinPly
&& beta > VALUE_TB_LOSS_IN_MAX_PLY)
{
@@ -924,13 +932,13 @@ Value Search::Worker::search(
}
}
Eval::NNUE::hint_common_parent_position(pos, networks);
Eval::NNUE::hint_common_parent_position(pos, networks, refreshTable);
}
moves_loop: // When in check, search starts here
// Step 12. A small Probcut idea, when we are in check (~4 Elo)
probCutBeta = beta + 436;
probCutBeta = beta + 452;
if (ss->inCheck && !PvNode && ttCapture && (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 4 && ttValue >= probCutBeta
&& std::abs(ttValue) < VALUE_TB_WIN_IN_MAX_PLY && std::abs(beta) < VALUE_TB_WIN_IN_MAX_PLY)
@@ -1013,7 +1021,7 @@ moves_loop: // When in check, search starts here
{
Piece capturedPiece = pos.piece_on(move.to_sq());
Value futilityValue =
ss->staticEval + 288 + 277 * lmrDepth + PieceValue[capturedPiece]
ss->staticEval + 285 + 277 * lmrDepth + PieceValue[capturedPiece]
+ thisThread->captureHistory[movedPiece][move.to_sq()][type_of(capturedPiece)]
/ 7;
if (futilityValue <= alpha)
@@ -1021,7 +1029,7 @@ moves_loop: // When in check, search starts here
}
// SEE based pruning for captures and checks (~11 Elo)
if (!pos.see_ge(move, -199 * depth))
if (!pos.see_ge(move, -203 * depth))
continue;
}
else
@@ -1041,10 +1049,10 @@ moves_loop: // When in check, search starts here
lmrDepth += history / 5285;
Value futilityValue =
ss->staticEval + (bestValue < ss->staticEval - 54 ? 128 : 58) + 131 * lmrDepth;
ss->staticEval + (bestValue < ss->staticEval - 54 ? 128 : 57) + 131 * lmrDepth;
// Futility pruning: parent node (~13 Elo)
if (!ss->inCheck && lmrDepth < 15 && futilityValue <= alpha)
if (!ss->inCheck && lmrDepth < 14 && futilityValue <= alpha)
{
if (bestValue <= futilityValue && std::abs(bestValue) < VALUE_TB_WIN_IN_MAX_PLY
&& futilityValue < VALUE_TB_WIN_IN_MAX_PLY)
@@ -1055,7 +1063,7 @@ moves_loop: // When in check, search starts here
lmrDepth = std::max(lmrDepth, 0);
// Prune moves with negative SEE (~4 Elo)
if (!pos.see_ge(move, -26 * lmrDepth * lmrDepth))
if (!pos.see_ge(move, -27 * lmrDepth * lmrDepth))
continue;
}
}
@@ -1075,11 +1083,11 @@ moves_loop: // When in check, search starts here
// so changing them requires tests at these types of time controls.
// Recursive singular search is avoided.
if (!rootNode && move == ttMove && !excludedMove
&& depth >= 4 - (thisThread->completedDepth > 32) + ss->ttPv
&& depth >= 4 - (thisThread->completedDepth > 33) + ss->ttPv
&& std::abs(ttValue) < VALUE_TB_WIN_IN_MAX_PLY && (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3)
{
Value singularBeta = ttValue - (64 + 59 * (ss->ttPv && !PvNode)) * depth / 64;
Value singularBeta = ttValue - (65 + 59 * (ss->ttPv && !PvNode)) * depth / 63;
Depth singularDepth = newDepth / 2;
ss->excludedMove = move;
@@ -1183,10 +1191,10 @@ moves_loop: // When in check, search starts here
ss->statScore = 2 * thisThread->mainHistory[us][move.from_to()]
+ (*contHist[0])[movedPiece][move.to_sq()]
+ (*contHist[1])[movedPiece][move.to_sq()]
+ (*contHist[3])[movedPiece][move.to_sq()] - 5007;
+ (*contHist[3])[movedPiece][move.to_sq()] - 5024;
// Decrease/increase reduction for moves with a good/bad history (~8 Elo)
r -= ss->statScore / 12901;
r -= ss->statScore / 13182;
// Step 17. Late moves reduction / extension (LMR, ~117 Elo)
if (depth >= 2 && moveCount > 1 + rootNode)
@@ -1323,7 +1331,7 @@ moves_loop: // When in check, search starts here
else
{
// Reduce other moves if we have found at least one score improvement (~2 Elo)
if (depth > 2 && depth < 12 && beta < 13132 && value > -13295)
if (depth > 2 && depth < 12 && beta < 13546 && value > -13478)
depth -= 2;
assert(depth > 0);
@@ -1368,7 +1376,7 @@ moves_loop: // When in check, search starts here
{
int bonus = (depth > 5) + (PvNode || cutNode) + ((ss - 1)->statScore < -14761)
+ ((ss - 1)->moveCount > 11)
+ (!ss->inCheck && bestValue <= ss->staticEval - 144);
+ (!ss->inCheck && bestValue <= ss->staticEval - 142);
update_continuation_histories(ss - 1, pos.piece_on(prevSq), prevSq,
stat_bonus(depth) * bonus);
thisThread->mainHistory[~us][((ss - 1)->currentMove).from_to()]
@@ -1463,7 +1471,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
// Step 2. Check for an immediate draw or maximum ply reached
if (pos.is_draw(ss->ply) || ss->ply >= MAX_PLY)
return (ss->ply >= MAX_PLY && !ss->inCheck)
? evaluate(networks, pos, thisThread->optimism[us])
? evaluate(networks, pos, refreshTable, thisThread->optimism[us])
: VALUE_DRAW;
assert(0 <= ss->ply && ss->ply < MAX_PLY);
@@ -1495,7 +1503,8 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
// Never assume anything about values stored in TT
unadjustedStaticEval = tte->eval();
if (unadjustedStaticEval == VALUE_NONE)
unadjustedStaticEval = evaluate(networks, pos, thisThread->optimism[us]);
unadjustedStaticEval =
evaluate(networks, pos, refreshTable, thisThread->optimism[us]);
ss->staticEval = bestValue =
to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos);
@@ -1508,7 +1517,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
{
// In case of null move search, use previous static eval with a different sign
unadjustedStaticEval = (ss - 1)->currentMove != Move::null()
? evaluate(networks, pos, thisThread->optimism[us])
? evaluate(networks, pos, refreshTable, thisThread->optimism[us])
: -(ss - 1)->staticEval;
ss->staticEval = bestValue =
to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos);
@@ -1528,7 +1537,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
if (bestValue > alpha)
alpha = bestValue;
futilityBase = ss->staticEval + 246;
futilityBase = ss->staticEval + 250;
}
const PieceToHistory* contHist[] = {(ss - 1)->continuationHistory,
@@ -1676,7 +1685,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
Depth Search::Worker::reduction(bool i, Depth d, int mn, int delta) {
int reductionScale = reductions[d] * reductions[mn];
return (reductionScale + 1123 - delta * 832 / rootDelta) / 1024 + (!i && reductionScale > 1025);
return (reductionScale + 1150 - delta * 832 / rootDelta) / 1024 + (!i && reductionScale > 1025);
}
TimePoint Search::Worker::elapsed() const {