// Transposition Table look up + alpha/beta update
TTLookupValue AlphaBeta::TTlookup(const GameState & state, AlphaBetaScore & alpha, AlphaBetaScore & beta, const size_t & depth)
{
TTEntry * entry = _TT->lookupScan(state.calculateHash(0), state.calculateHash(1));
if (entry && (entry->getDepth() == depth))
{
// get the value and type of the entry
AlphaBetaScore TTvalue = entry->getScore();
// set alpha and beta depending on the type of entry in the TT
if (entry->getType() == TTEntry::LOWER)
{
if (TTvalue > alpha)
{
alpha = TTvalue;
}
}
else if (entry->getType() == TTEntry::UPPER)
{
if (TTvalue < beta)
{
beta = TTvalue;
}
}
else
{
printf("LOL\n");
alpha = TTvalue;
beta = TTvalue;
}
if (alpha >= beta)
{
// this will be a cut
_results.ttcuts++;
return TTLookupValue(true, true, entry);
}
else
{
// found but no cut
_results.ttFoundNoCut++;
return TTLookupValue(true, false, entry);
}
}
else if (entry)
{
_results.ttFoundLessDepth++;
return TTLookupValue(true, false, entry);
}
return TTLookupValue(false, false, entry);
}
void
TranspositionTable::extractPVMoves(const Position& rootPos, const Move& mFirst, std::vector<Move>& pv) {
Position pos(rootPos);
Move m(mFirst);
UndoInfo ui;
std::vector<U64> hashHistory;
while (true) {
pv.push_back(m);
pos.makeMove(m, ui);
if (contains(hashHistory, pos.zobristHash()))
break;
hashHistory.push_back(pos.zobristHash());
TTEntry ent;
ent.clear();
probe(pos.historyHash(), ent);
if (ent.getType() == TType::T_EMPTY)
break;
ent.getMove(m);
MoveList moves;
MoveGen::pseudoLegalMoves(pos, moves);
MoveGen::removeIllegal(pos, moves);
bool contains = false;
for (int mi = 0; mi < moves.size; mi++)
if (moves[mi].equals(m)) {
contains = true;
break;
}
if (!contains)
break;
}
}
/** Extract the PV starting from posIn, using hash entries, both exact scores and bounds. */
std::string
TranspositionTable::extractPV(const Position& posIn) {
std::string ret;
Position pos(posIn);
bool first = true;
TTEntry ent;
ent.clear();
probe(pos.historyHash(), ent);
UndoInfo ui;
std::vector<U64> hashHistory;
bool repetition = false;
while (ent.getType() != TType::T_EMPTY) {
Move m;
ent.getMove(m);
MoveList moves;
MoveGen::pseudoLegalMoves(pos, moves);
MoveGen::removeIllegal(pos, moves);
bool valid = false;
for (int mi = 0; mi < moves.size; mi++)
if (moves[mi].equals(m)) {
valid = true;
break;
}
if (!valid)
break;
if (repetition)
break;
if (!first)
ret += ' ';
if (ent.getType() == TType::T_LE)
ret += '<';
else if (ent.getType() == TType::T_GE)
ret += '>';
std::string moveStr = TextIO::moveToString(pos, m, false);
ret += moveStr;
pos.makeMove(m, ui);
if (contains(hashHistory, pos.zobristHash()))
repetition = true;
hashHistory.push_back(pos.zobristHash());
probe(pos.historyHash(), ent);
first = false;
}
return ret;
}
void
TranspositionTable::insert(U64 key, const Move& sm, int type, int ply, int depth, int evalScore) {
if (depth < 0) depth = 0;
size_t idx0 = getIndex(key);
U64 key2 = getStoredKey(key);
TTEntry ent0, ent1;
ent0.load(table[idx0]);
size_t idx = idx0;
TTEntry* ent = &ent0;
if (ent0.getKey() != key2) {
size_t idx1 = idx0 ^ 1;
ent1.load(table[idx1]);
idx = idx1;
ent = &ent1;
if (ent1.getKey() != key2)
if (ent1.betterThan(ent0, generation)) {
idx = idx0;
ent = &ent0;
}
}
bool doStore = true;
if ((ent->getKey() == key2) && (ent->getDepth() > depth) && (ent->getType() == type)) {
if (type == TType::T_EXACT)
doStore = false;
else if ((type == TType::T_GE) && (sm.score() <= ent->getScore(ply)))
doStore = false;
else if ((type == TType::T_LE) && (sm.score() >= ent->getScore(ply)))
doStore = false;
}
if (doStore) {
if ((ent->getKey() != key2) || (sm.from() != sm.to()))
ent->setMove(sm);
ent->setKey(key2);
ent->setScore(sm.score(), ply);
ent->setDepth(depth);
ent->setGeneration((S8)generation);
ent->setType(type);
ent->setEvalScore(evalScore);
ent->store(table[idx]);
}
}
void
TranspositionTable::printStats() const {
int unused = 0;
int thisGen = 0;
std::vector<int> depHist;
const int maxDepth = 20*8;
depHist.resize(maxDepth);
for (size_t i = 0; i < table.size(); i++) {
TTEntry ent;
ent.load(table[i]);
if (ent.getType() == TType::T_EMPTY) {
unused++;
} else {
if (ent.getGeneration() == generation)
thisGen++;
if (ent.getDepth() < maxDepth)
depHist[ent.getDepth()]++;
}
}
double w = 100.0 / table.size();
std::stringstream ss;
ss.precision(2);
ss << std::fixed << "hstat: size:" << table.size()
<< " unused:" << unused << " (" << (unused*w) << "%)"
<< " thisGen:" << thisGen << " (" << (thisGen*w) << "%)" << std::endl;
cout << ss.str();
for (int i = 0; i < maxDepth; i++) {
int c = depHist[i];
if (c > 0) {
std::stringstream ss;
ss.precision(2);
ss << std::setw(4) << i
<< ' ' << std::setw(8) << c
<< " " << std::setw(6) << std::fixed << (c*w);
std::cout << "hstat:" << ss.str() << std::endl;
}
}
}
