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Increase LMR when not improving

Browse source 
Apply to LMR the same Eelco's idea
applied to move count pruning.

This is the result of a series of
attempts started by Thomas Kolarik.

Passed both short TC
LLR: 2.95 (-2.94, 2.94)
Total: 5675 W: 1241 L: 1117 D: 3317


And long TC:
LLR: 2.95 (-2.94, 2.94)
Total: 8748 W: 1689 L: 1539 D: 5520

bench: 4356801
This commit is contained in:
Marco Costalba 2013-08-08 10:28:48 +02:00
parent 56d2c3844a
commit fff6b9f061
1 changed files with 13 additions and 7 deletions
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20
src/search.cpp
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@ -75,11 +75,11 @@ namespace {
}
// Reduction lookup tables (initialized at startup) and their access function
int8_t Reductions[2][64][64]; // [pv][depth][moveNumber]
int8_t Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber]
template <bool PvNode> inline Depth reduction(Depth d, int mn) {
template <bool PvNode> inline Depth reduction(bool i, Depth d, int mn) {
return (Depth) Reductions[PvNode][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
size_t PVSize, PVIdx;
@ -136,8 +136,14 @@ void Search::init() {
{
double pvRed = log(double(hd)) * log(double(mc)) / 3.0;
double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
Reductions[1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
Reductions[0][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
Reductions[1][1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
Reductions[0][1][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
Reductions[1][0][hd][mc] = Reductions[1][1][hd][mc];
Reductions[0][0][hd][mc] = Reductions[0][1][hd][mc];
if (Reductions[0][0][hd][mc] > 2 * ONE_PLY)
Reductions[0][0][hd][mc] += ONE_PLY;
}
// Init futility margins array
@ -878,7 +884,7 @@ moves_loop: // When in check and at SpNode search starts from here
// Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
Depth predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
futilityValue = ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
+ Gains[pos.piece_moved(move)][to_sq(move)];
@ -937,7 +943,7 @@ moves_loop: // When in check and at SpNode search starts from here
&& move != ss->killers[0]
&& move != ss->killers[1])
{
ss->reduction = reduction<PvNode>(depth, moveCount);
ss->reduction = reduction<PvNode>(improving, depth, moveCount);
if (!PvNode && cutNode)
ss->reduction += ONE_PLY;