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Remove use of half-ply reductions from LMR, Null-move, IID and

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Singular extensions.

STC:
ELO: 3.80 +-3.1 (95%) LOS: 99.2%
Total: 19727 W: 4190 L: 3974 D: 11563

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 7647 W: 1356 L: 1214 D: 5077

Bench: 6545733

Resolves #55
This commit is contained in:
Uri Blass 2014-09-28 04:33:28 +08:00 • committed by Gary Linscott
parent 7ed15af371
commit ea9c424bba
1 changed files with 6 additions and 10 deletions
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16
src/search.cpp
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@ -127,17 +127,14 @@ void Search::init() {
{ {
double pvRed = 0.00 + log(double(hd)) * log(double(mc)) / 3.00; double pvRed = 0.00 + log(double(hd)) * log(double(mc)) / 3.00;
double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25; double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
Reductions[1][1][hd][mc] = int8_t( pvRed >= 1.0 ? pvRed * int(ONE_PLY) : 0); Reductions[1][1][hd][mc] = int8_t( pvRed >= 1.0 ? pvRed+0.5: 0)*int(ONE_PLY);
Reductions[0][1][hd][mc] = int8_t(nonPVRed >= 1.0 ? nonPVRed * int(ONE_PLY) : 0); Reductions[0][1][hd][mc] = int8_t(nonPVRed >= 1.0 ? nonPVRed+0.5: 0)*int(ONE_PLY);
Reductions[1][0][hd][mc] = Reductions[1][1][hd][mc]; Reductions[1][0][hd][mc] = Reductions[1][1][hd][mc];
Reductions[0][0][hd][mc] = Reductions[0][1][hd][mc]; Reductions[0][0][hd][mc] = Reductions[0][1][hd][mc];
if (Reductions[0][0][hd][mc] > 2 * ONE_PLY) if (Reductions[0][0][hd][mc] >= 2 * ONE_PLY)
Reductions[0][0][hd][mc] += ONE_PLY; Reductions[0][0][hd][mc] += ONE_PLY;
else if (Reductions[0][0][hd][mc] > 1 * ONE_PLY)
Reductions[0][0][hd][mc] += ONE_PLY / 2;
} }
// Init futility move count array // Init futility move count array
@ -565,8 +562,7 @@ namespace {
assert(eval - beta >= 0); assert(eval - beta >= 0);
// Null move dynamic reduction based on depth and value // Null move dynamic reduction based on depth and value
Depth R = 3 * ONE_PLY Depth R = (3 + (depth / 8 )) * ONE_PLY
+ depth / 4
+ std::min(int(eval - beta) / PawnValueMg, 3) * ONE_PLY; + std::min(int(eval - beta) / PawnValueMg, 3) * ONE_PLY;
pos.do_null_move(st); pos.do_null_move(st);
@ -633,7 +629,7 @@ namespace {
&& (PvNode || ss->staticEval + 256 >= beta)) && (PvNode || ss->staticEval + 256 >= beta))
{ {
Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4); Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
d = (d / 2) * 2; // Round to nearest full-ply
ss->skipNullMove = true; ss->skipNullMove = true;
search<PvNode ? PV : NonPV, false>(pos, ss, alpha, beta, d, true); search<PvNode ? PV : NonPV, false>(pos, ss, alpha, beta, d, true);
ss->skipNullMove = false; ss->skipNullMove = false;
@ -735,7 +731,7 @@ moves_loop: // When in check and at SpNode search starts from here
Value rBeta = ttValue - int(depth); Value rBeta = ttValue - int(depth);
ss->excludedMove = move; ss->excludedMove = move;
ss->skipNullMove = true; ss->skipNullMove = true;
value = search<NonPV, false>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); value = search<NonPV, false>(pos, ss, rBeta - 1, rBeta, (depth / 4) * 2, cutNode);
ss->skipNullMove = false; ss->skipNullMove = false;
ss->excludedMove = MOVE_NONE; ss->excludedMove = MOVE_NONE;