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Depth Tweak and tuning

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tunes reduction related parameters, and introduces more reduction on found good moves.

credit for this patch goes also to candirufish Yoshie2000 dubslow peregrineshahin Vizvezdenec

Passed STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 38424 W: 10346 L: 10040 D: 18038
Ptnml(0-2): 103, 4111, 10473, 4427, 98
https://tests.stockfishchess.org/tests/view/642ca74277ff3301150db511

Passed LTC:
LLR: 2.97 (-2.94,2.94) <0.50,2.50>
Total: 136968 W: 37151 L: 36660 D: 63157
Ptnml(0-2): 43, 13052, 41808, 13533, 48
https://tests.stockfishchess.org/tests/view/642d632377ff3301150dddbe

closes https://github.com/official-stockfish/Stockfish/pull/4499

bench: 3672914
This commit is contained in:
FauziAkram 2023-04-06 00:35:05 +03:00 • committed by Joost VandeVondele
parent 510aca1ef6
commit 59f2085469
1 changed files with 12 additions and 10 deletions
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22
src/search.cpp
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@ -72,7 +72,7 @@ namespace {
Depth reduction(bool i, Depth d, int mn, Value delta, Value rootDelta) {
int r = Reductions[d] * Reductions[mn];
return (r + 1449 - int(delta) * 1001 / int(rootDelta)) / 1024 + (!i && r > 941);
return (r + 1449 - int(delta) * 937 / int(rootDelta)) / 1024 + (!i && r > 941);
}
constexpr int futility_move_count(bool improving, Depth depth) {
@ -82,7 +82,7 @@ namespace {
// History and stats update bonus, based on depth
int stat_bonus(Depth d) {
return std::min(341 * d - 470, 1855);
return std::min(341 * d - 470, 1710);
}
// Add a small random component to draw evaluations to avoid 3-fold blindness
@ -775,7 +775,7 @@ namespace {
// 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 - 426 - 252 * depth * depth)
if (eval < alpha - 426 - 256 * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha)
@ -797,7 +797,7 @@ namespace {
&& (ss-1)->statScore < 18755
&& eval >= beta
&& eval >= ss->staticEval
&& ss->staticEval >= beta - 19 * depth - improvement / 13 + 253 + complexity / 25
&& ss->staticEval >= beta - 20 * depth - improvement / 13 + 253 + complexity / 25
&& !excludedMove
&& pos.non_pawn_material(us)
&& (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
@ -805,7 +805,7 @@ namespace {
assert(eval - beta >= 0);
// Null move dynamic reduction based on depth, eval and complexity of position
Depth R = std::min(int(eval - beta) / 168, 6) + depth / 3 + 4 - (complexity > 825);
Depth R = std::min(int(eval - beta) / 172, 6) + depth / 3 + 4 - (complexity > 825);
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
@ -1333,16 +1333,18 @@ moves_loop: // When in check, search starts here
if (PvNode && value < beta) // Update alpha! Always alpha < beta
{
alpha = value;
// Reduce other moves if we have found at least one score improvement (~1 Elo)
if ( depth > 1
&& depth < 6
&& beta < 10534
&& alpha > -10534)
depth -= 1;
&& ((improving && complexity > 971) || (value < (5 * alpha + 75 * beta) / 87) || depth < 6)
&& beta < 12535
&& value > -12535) {
bool extraReduction = depth > 2 && alpha > -12535 && bestValue != -VALUE_INFINITE && (value - bestValue) > (7 * (beta - alpha)) / 8;
depth -= 1 + extraReduction;
}
assert(depth > 0);
alpha = value;
}
else
{