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Combo of various parameter tweaks
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Combination of parameter tweaks in search, evaluation and time management.
Original patches by snicolet xoto10 lonfom169 and Vizvezdenec.

Includes:

* Use bigger grain of positional evaluation more frequently (up to 1 exchange difference in non-pawn-material);
* More extra time according to increment;
* Increase margin for singular extensions;
* Do more aggresive parent node futility pruning.

Passed STC
https://tests.stockfishchess.org/tests/view/6147deab3733d0e0dd9f313d
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 45488 W: 11691 L: 11450 D: 22347
Ptnml(0-2): 145, 5208, 11824, 5395, 172

Passed LTC
https://tests.stockfishchess.org/tests/view/6147f1d53733d0e0dd9f3141
LLR: 2.94 (-2.94,2.94) <0.50,3.50>
Total: 62520 W: 15808 L: 15482 D: 31230
Ptnml(0-2): 43, 6439, 17960, 6785, 33

closes official-stockfish#3710

bench 5575265
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Vizvezdenec authored and Joachim26 committed Mar 28, 2023
1 parent 2938b69 commit 363e1b6
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Showing 3 changed files with 5 additions and 5 deletions.
2 changes: 1 addition & 1 deletion src/nnue/evaluate_nnue.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -168,7 +168,7 @@ namespace Stockfish::Eval::NNUE {
int positional = output[0];

int delta_npm = abs(pos.non_pawn_material(WHITE) - pos.non_pawn_material(BLACK));
int entertainment = (adjusted && delta_npm <= BishopValueMg - KnightValueMg ? 7 : 0);
int entertainment = (adjusted && delta_npm <= RookValueMg - BishopValueMg ? 7 : 0);

int A = 128 - entertainment;
int B = 128 + entertainment;
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6 changes: 3 additions & 3 deletions src/search.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -1031,8 +1031,8 @@ namespace {

// Futility pruning: parent node (~5 Elo)
if ( !ss->inCheck
&& lmrDepth < 7
&& ss->staticEval + 172 + 157 * lmrDepth <= alpha)
&& lmrDepth < 8
&& ss->staticEval + 172 + 145 * lmrDepth <= alpha)
continue;

// Prune moves with negative SEE (~20 Elo)
Expand All @@ -1057,7 +1057,7 @@ namespace {
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3)
{
Value singularBeta = ttValue - 2 * depth;
Value singularBeta = ttValue - 3 * depth;
Depth singularDepth = (depth - 1) / 2;

ss->excludedMove = move;
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2 changes: 1 addition & 1 deletion src/timeman.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -69,7 +69,7 @@ void TimeManagement::init(Search::LimitsType& limits, Color us, int ply) {
limits.time[us] + limits.inc[us] * (mtg - 1) - moveOverhead * (2 + mtg));

// Use extra time with larger increments
double optExtra = std::clamp(1.0 + 10.0 * limits.inc[us] / limits.time[us], 1.0, 1.1);
double optExtra = std::clamp(1.0 + 12.0 * limits.inc[us] / limits.time[us], 1.0, 1.12);

// A user may scale time usage by setting UCI option "Slow Mover"
// Default is 100 and changing this value will probably lose elo.
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