Skip to content

Commit

Permalink
VVLTC search tune
Browse files Browse the repository at this point in the history 
Result of 32k games of tuning at 60+0.6 8-thread. Link to the tuning
attempt:
https://tests.stockfishchess.org/tests/view/65def7b04b19edc854ebdec8

Passed VVLTC first SPRT:
https://tests.stockfishchess.org/tests/view/65e51b53416ecd92c162ab7f
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 37570 W: 9613 L: 9342 D: 18615
Ptnml(0-2): 2, 3454, 11601, 3727, 1

Passed VVLTC second SPRT:
https://tests.stockfishchess.org/tests/view/65e87d1c0ec64f0526c3eb39
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 123158 W: 31463 L: 31006 D: 60689
Ptnml(0-2): 5, 11589, 37935, 12044, 6

Note: The small net and psqt-only thresholds have been moved to
evaluate.h. The reasoning is that these values are used in both
`evaluate.cpp` and `evaluate_nnue.cpp`, and thus unifying their usage
avoids inconsistencies during testing, where one occurrence is changed
without the other (this happened during the search tune SPRT).

closes official-stockfish#5101

Bench: 1741218
  • Loading branch information
@XInTheDark @Disservin
XInTheDark authored and Disservin committed Mar 11, 2024
1 parent b6dfd6b commit 10e2732
Show file tree
Hide file tree
Showing 4 changed files with 43 additions and 42 deletions.
4 changes: 2 additions & 2 deletions src/evaluate.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -193,8 +193,8 @@ Value Eval::evaluate(const Position& pos, int optimism) {
assert(!pos.checkers());

int simpleEval = simple_eval(pos, pos.side_to_move());
bool smallNet = std::abs(simpleEval) > 1050;
bool psqtOnly = std::abs(simpleEval) > 2500;
bool smallNet = std::abs(simpleEval) > SmallNetThreshold;
bool psqtOnly = std::abs(simpleEval) > PsqtOnlyThreshold;

int nnueComplexity;

Expand Down
2 changes: 2 additions & 0 deletions src/evaluate.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,8 @@ class OptionsMap;

namespace Eval {

constexpr inline int SmallNetThreshold = 1139, PsqtOnlyThreshold = 2500;

std::string trace(Position& pos);

int simple_eval(const Position& pos, Color c);
Expand Down
4 changes: 2 additions & 2 deletions src/nnue/evaluate_nnue.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -179,8 +179,8 @@ write_parameters(std::ostream& stream, NetSize netSize, const std::string& netDe
void hint_common_parent_position(const Position& pos) {

int simpleEvalAbs = std::abs(simple_eval(pos, pos.side_to_move()));
if (simpleEvalAbs > 1050)
featureTransformerSmall->hint_common_access(pos, simpleEvalAbs > 2500);
if (simpleEvalAbs > Eval::SmallNetThreshold)
featureTransformerSmall->hint_common_access(pos, simpleEvalAbs > Eval::PsqtOnlyThreshold);
else
featureTransformerBig->hint_common_access(pos, false);
}
Expand Down
75 changes: 37 additions & 38 deletions src/search.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,7 @@ namespace {

// Futility margin
Value futility_margin(Depth d, bool noTtCutNode, bool improving, bool oppWorsening) {
Value futilityMult = 117 - 44 * noTtCutNode;
Value futilityMult = 121 - 43 * noTtCutNode;
Value improvingDeduction = 3 * improving * futilityMult / 2;
Value worseningDeduction = (331 + 45 * improving) * oppWorsening * futilityMult / 1024;

Expand All @@ -69,15 +69,15 @@ constexpr int futility_move_count(bool improving, Depth depth) {
// Add correctionHistory value to raw staticEval and guarantee evaluation does not hit the tablebase range
Value to_corrected_static_eval(Value v, const Worker& w, const Position& pos) {
auto cv = w.correctionHistory[pos.side_to_move()][pawn_structure_index<Correction>(pos)];
v += cv * std::abs(cv) / 12475;
v += cv * std::abs(cv) / 10759;
return std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
}

// History and stats update bonus, based on depth
int stat_bonus(Depth d) { return std::min(246 * d - 351, 1136); }
int stat_bonus(Depth d) { return std::min(249 * d - 327, 1192); }

// History and stats update malus, based on depth
int stat_malus(Depth d) { return std::min(519 * d - 306, 1258); }
int stat_malus(Depth d) { return std::min(516 * d - 299, 1432); }

// 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); }
Expand Down Expand Up @@ -300,12 +300,12 @@ void Search::Worker::iterative_deepening() {

// Reset aspiration window starting size
Value avg = rootMoves[pvIdx].averageScore;
delta = 9 + avg * avg / 12487;
delta = 9 + avg * avg / 12804;
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] = 134 * avg / (std::abs(avg) + 97);
optimism[us] = 131 * avg / (std::abs(avg) + 90);
optimism[~us] = -optimism[us];

// Start with a small aspiration window and, in the case of a fail
Expand Down Expand Up @@ -500,7 +500,7 @@ void Search::Worker::clear() {
h->fill(-71);

for (size_t i = 1; i < reductions.size(); ++i)
reductions[i] = int((18.79 + std::log(size_t(options["Threads"])) / 2) * std::log(i));
reductions[i] = int((19.02 + std::log(size_t(options["Threads"])) / 2) * std::log(i));
}


Expand Down Expand Up @@ -731,7 +731,7 @@ Value Search::Worker::search(
// Use static evaluation difference to improve quiet move ordering (~9 Elo)
if (((ss - 1)->currentMove).is_ok() && !(ss - 1)->inCheck && !priorCapture)
{
int bonus = std::clamp(-14 * int((ss - 1)->staticEval + ss->staticEval), -1723, 1455);
int bonus = std::clamp(-14 * int((ss - 1)->staticEval + ss->staticEval), -1621, 1237);
bonus = bonus > 0 ? 2 * bonus : bonus / 2;
thisThread->mainHistory[~us][((ss - 1)->currentMove).from_to()] << bonus;
if (type_of(pos.piece_on(prevSq)) != PAWN && ((ss - 1)->currentMove).type_of() != PROMOTION)
Expand All @@ -754,7 +754,7 @@ 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 - 438 - (332 - 154 * ((ss + 1)->cutoffCnt > 3)) * depth * depth)
if (eval < alpha - 462 - (296 - 145 * ((ss + 1)->cutoffCnt > 3)) * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha)
Expand All @@ -763,24 +763,23 @@ Value Search::Worker::search(

// Step 8. Futility pruning: child node (~40 Elo)
// The depth condition is important for mate finding.
if (!ss->ttPv && depth < 11
if (!ss->ttPv && depth < 12
&& eval - futility_margin(depth, cutNode && !ss->ttHit, improving, opponentWorsening)
- (ss - 1)->statScore / 314
- (ss - 1)->statScore / 287
>= beta
&& eval >= beta && eval < 30016 // smaller than TB wins
&& (!ttMove || ttCapture))
&& 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 < 16620
&& eval >= beta && eval >= ss->staticEval && ss->staticEval >= beta - 21 * depth + 330
if (!PvNode && (ss - 1)->currentMove != Move::null() && (ss - 1)->statScore < 16211
&& eval >= beta && eval >= ss->staticEval && ss->staticEval >= beta - 20 * depth + 314
&& !excludedMove && pos.non_pawn_material(us) && ss->ply >= thisThread->nmpMinPly
&& beta > VALUE_TB_LOSS_IN_MAX_PLY)
{
assert(eval - beta >= 0);

// Null move dynamic reduction based on depth and eval
Depth R = std::min(int(eval - beta) / 154, 6) + depth / 3 + 4;
Depth R = std::min(int(eval - beta) / 151, 6) + depth / 3 + 4;

ss->currentMove = Move::null();
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
Expand Down Expand Up @@ -828,7 +827,7 @@ Value Search::Worker::search(
// Step 11. ProbCut (~10 Elo)
// If we have a good enough capture (or queen promotion) and a reduced search returns a value
// much above beta, we can (almost) safely prune the previous move.
probCutBeta = beta + 181 - 68 * improving;
probCutBeta = beta + 164 - 62 * improving;
if (
!PvNode && depth > 3
&& std::abs(beta) < VALUE_TB_WIN_IN_MAX_PLY
Expand Down Expand Up @@ -884,7 +883,7 @@ Value Search::Worker::search(
moves_loop: // When in check, search starts here

// Step 12. A small Probcut idea, when we are in check (~4 Elo)
probCutBeta = beta + 452;
probCutBeta = beta + 410;
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)
Expand Down Expand Up @@ -967,15 +966,15 @@ Value Search::Worker::search(
{
Piece capturedPiece = pos.piece_on(move.to_sq());
int futilityEval =
ss->staticEval + 277 + 292 * lmrDepth + PieceValue[capturedPiece]
ss->staticEval + 298 + 288 * lmrDepth + PieceValue[capturedPiece]
+ thisThread->captureHistory[movedPiece][move.to_sq()][type_of(capturedPiece)]
/ 7;
if (futilityEval < alpha)
continue;
}

// SEE based pruning for captures and checks (~11 Elo)
if (!pos.see_ge(move, -197 * depth))
if (!pos.see_ge(move, -202 * depth))
continue;
}
else
Expand All @@ -987,17 +986,17 @@ Value Search::Worker::search(
+ thisThread->pawnHistory[pawn_structure_index(pos)][movedPiece][move.to_sq()];

// Continuation history based pruning (~2 Elo)
if (lmrDepth < 6 && history < -4211 * depth)
if (lmrDepth < 6 && history < -4125 * depth)
continue;

history += 2 * thisThread->mainHistory[us][move.from_to()];

lmrDepth += history / 6437;
lmrDepth += history / 5686;

// Futility pruning: parent node (~13 Elo)
if (!ss->inCheck && lmrDepth < 15
&& ss->staticEval + (bestValue < ss->staticEval - 57 ? 144 : 57)
+ 121 * lmrDepth
&& ss->staticEval + (bestValue < ss->staticEval - 55 ? 153 : 58)
+ 118 * lmrDepth
<= alpha)
continue;

Expand All @@ -1024,11 +1023,11 @@ Value Search::Worker::search(
// 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 > 30) + ss->ttPv
&& depth >= 4 - (thisThread->completedDepth > 29) + ss->ttPv
&& std::abs(ttValue) < VALUE_TB_WIN_IN_MAX_PLY && (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3)
{
Value singularBeta = ttValue - (60 + 54 * (ss->ttPv && !PvNode)) * depth / 64;
Value singularBeta = ttValue - (58 + 55 * (ss->ttPv && !PvNode)) * depth / 64;
Depth singularDepth = newDepth / 2;

ss->excludedMove = move;
Expand All @@ -1044,7 +1043,7 @@ Value Search::Worker::search(
if (!PvNode && ss->multipleExtensions <= 16)
{
extension = 2 + (value < singularBeta - 78 && !ttCapture);
depth += depth < 16;
depth += depth < 14;
}
if (PvNode && !ttCapture && ss->multipleExtensions <= 5
&& value < singularBeta - 50)
Expand Down Expand Up @@ -1082,7 +1081,7 @@ Value Search::Worker::search(
else if (PvNode && move == ttMove && move.to_sq() == prevSq
&& thisThread->captureHistory[movedPiece][move.to_sq()]
[type_of(pos.piece_on(move.to_sq()))]
> 4394)
> 4315)
extension = 1;
}

Expand Down Expand Up @@ -1136,10 +1135,10 @@ Value Search::Worker::search(
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()] - 4392;
+ (*contHist[3])[movedPiece][move.to_sq()] - 4587;

// Decrease/increase reduction for moves with a good/bad history (~8 Elo)
r -= ss->statScore / 14189;
r -= ss->statScore / 12372;

// Step 17. Late moves reduction / extension (LMR, ~117 Elo)
if (depth >= 2 && moveCount > 1 + rootNode)
Expand All @@ -1158,7 +1157,7 @@ Value Search::Worker::search(
{
// Adjust full-depth search based on LMR results - if the result
// was good enough search deeper, if it was bad enough search shallower.
const bool doDeeperSearch = value > (bestValue + 49 + 2 * newDepth); // (~1 Elo)
const bool doDeeperSearch = value > (bestValue + 48 + 2 * newDepth); // (~1 Elo)
const bool doShallowerSearch = value < bestValue + newDepth; // (~2 Elo)

newDepth += doDeeperSearch - doShallowerSearch;
Expand Down Expand Up @@ -1277,7 +1276,7 @@ Value Search::Worker::search(
else
{
// Reduce other moves if we have found at least one score improvement (~2 Elo)
if (depth > 2 && depth < 13 && beta < 13652 && value > -12761)
if (depth > 2 && depth < 12 && beta < 13665 && value > -12276)
depth -= 2;

assert(depth > 0);
Expand Down Expand Up @@ -1320,8 +1319,8 @@ Value Search::Worker::search(
// Bonus for prior countermove that caused the fail low
else if (!priorCapture && prevSq != SQ_NONE)
{
int bonus = (depth > 5) + (PvNode || cutNode) + ((ss - 1)->statScore < -15736)
+ ((ss - 1)->moveCount > 11);
int bonus = (depth > 5) + (PvNode || cutNode) + ((ss - 1)->statScore < -14446)
+ ((ss - 1)->moveCount > 10);
update_continuation_histories(ss - 1, pos.piece_on(prevSq), prevSq,
stat_bonus(depth) * bonus);
thisThread->mainHistory[~us][((ss - 1)->currentMove).from_to()]
Expand Down Expand Up @@ -1478,7 +1477,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
if (bestValue > alpha)
alpha = bestValue;

futilityBase = ss->staticEval + 206;
futilityBase = ss->staticEval + 221;
}

const PieceToHistory* contHist[] = {(ss - 1)->continuationHistory,
Expand Down Expand Up @@ -1558,7 +1557,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
continue;

// Do not search moves with bad enough SEE values (~5 Elo)
if (!pos.see_ge(move, -74))
if (!pos.see_ge(move, -79))
continue;
}

Expand Down Expand Up @@ -1626,7 +1625,7 @@ 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 + 1118 - delta * 793 / rootDelta) / 1024 + (!i && reductionScale > 863);
return (reductionScale + 1091 - delta * 759 / rootDelta) / 1024 + (!i && reductionScale > 952);
}

namespace {
Expand Down Expand Up @@ -1715,7 +1714,7 @@ void update_all_stats(const Position& pos,

if (!pos.capture_stage(bestMove))
{
int bestMoveBonus = bestValue > beta + 166 ? quietMoveBonus // larger bonus
int bestMoveBonus = bestValue > beta + 167 ? quietMoveBonus // larger bonus
: stat_bonus(depth); // smaller bonus

// Increase stats for the best move in case it was a quiet move
Expand Down

0 comments on commit 10e2732

Please sign in to comment.