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Code Issues Releases Wiki Activity

Reintroduce gains

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This seems a die hard idea :-)

Passed both short TC
LLR: 2.97 (-2.94,2.94) [-1.50,4.50]
Total: 17485 W: 3307 L: 3156 D: 11022

And long TC
LLR: 2.97 (-2.94,2.94) [0.00,6.00]
Total: 38181 W: 6002 L: 5729 D: 26450

bench: 8659830
This commit is contained in:
Joona Kiiski 2013-11-10 14:53:23 +00:00 • committed by Marco Costalba
parent 4ef6b2c32a
commit b9768b8bc5
2 changed files with 31 additions and 14 deletions
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17
src/movepick.h
View file

@ -30,13 +30,14 @@
/// The Stats struct stores moves statistics. According to the template parameter
/// the class can store History and Countermoves. History records how often
/// the class can store History, Gains and Countermoves. History records how often
/// different moves have been successful or unsuccessful during the current search
/// and is used for reduction and move ordering decisions.
/// and is used for reduction and move ordering decisions. Gains records the move's
/// best evaluation gain from one ply to the next and is used for pruning decisions.
/// Countermoves store the move that refute a previous one. Entries are stored
/// according only to moving piece and destination square, hence two moves with
/// different origin but same destination and piece will be considered identical.
template<typename T>
template<bool Gain, typename T>
struct Stats {
static const Value Max = Value(2000);
@ -55,7 +56,10 @@ struct Stats {
void update(Piece p, Square to, Value v) {
if (abs(table[p][to] + v) < Max)
if (Gain)
table[p][to] = std::max(v, table[p][to] - 1);
else if (abs(table[p][to] + v) < Max)
table[p][to] += v;
}
@ -63,8 +67,9 @@ private:
T table[PIECE_NB][SQUARE_NB];
};
typedef Stats<Value> HistoryStats;
typedef Stats<std::pair<Move, Move> > CountermovesStats;
typedef Stats< true, Value> GainsStats;
typedef Stats<false, Value> HistoryStats;
typedef Stats<false, std::pair<Move, Move> > CountermovesStats;
/// MovePicker class is used to pick one pseudo legal move at a time from the

28
src/search.cpp
View file

@ -82,6 +82,7 @@ namespace {
double BestMoveChanges;
Value DrawValue[COLOR_NB];
HistoryStats History;
GainsStats Gains;
CountermovesStats Countermoves;
template <NodeType NT>
@ -293,6 +294,7 @@ namespace {
Value bestValue, alpha, beta, delta;
std::memset(ss-2, 0, 5 * sizeof(Stack));
(ss-1)->currentMove = MOVE_NULL; // Hack to skip update gains
depth = 0;
BestMoveChanges = 0;
@ -301,6 +303,7 @@ namespace {
TT.new_search();
History.clear();
Gains.clear();
Countermoves.clear();
PVSize = Options["MultiPV"];
@ -487,9 +490,8 @@ namespace {
SplitPoint* splitPoint;
Key posKey;
Move ttMove, move, excludedMove, bestMove, threatMove;
Depth ext, newDepth;
Value bestValue, value, ttValue;
Value eval, nullValue;
Depth ext, newDepth, predictedDepth;
Value bestValue, value, ttValue, eval, nullValue, futilityValue;
bool inCheck, givesCheck, pvMove, singularExtensionNode, improving;
bool captureOrPromotion, dangerous, doFullDepthSearch;
int moveCount, quietCount;
@ -601,6 +603,16 @@ namespace {
TT.store(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, ss->staticEval);
}
if ( !pos.captured_piece_type()
&& ss->staticEval != VALUE_NONE
&& (ss-1)->staticEval != VALUE_NONE
&& (move = (ss-1)->currentMove) != MOVE_NULL
&& type_of(move) == NORMAL)
{
Square to = to_sq(move);
Gains.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
}
// Step 6. Razoring (skipped when in check)
if ( !PvNode
&& depth < 4 * ONE_PLY
@ -847,12 +859,13 @@ moves_loop: // When in check and at SpNode search starts from here
continue;
}
Depth predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
// Futility pruning: parent node
if (predictedDepth < 7 * ONE_PLY)
{
Value futilityValue = ss->staticEval + futility_margin(predictedDepth) + Value(128);
futilityValue = ss->staticEval + futility_margin(predictedDepth)
+ Value(128) + Gains[pos.moved_piece(move)][to_sq(move)];
if (futilityValue <= alpha)
{
@ -869,8 +882,7 @@ moves_loop: // When in check and at SpNode search starts from here
}
// Prune moves with negative SEE at low depths
if ( predictedDepth < 4 * ONE_PLY
&& pos.see_sign(move) < 0)
if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < 0)
{
if (SpNode)
splitPoint->mutex.lock();
@ -883,7 +895,7 @@ moves_loop: // When in check and at SpNode search starts from here
// Check for legality only before to do the move
if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
{
--moveCount;
moveCount--;
continue;
}