std::string pgn::Ply::toStdString() const
{
std::string res;
if (isLongCastle())
{
res += "O-O-O";
if (isCheckMate())
res += "#";
else if (isCheck())
res += "+";
}
else if (isShortCastle())
{
res += "O-O";
if (isCheckMate())
res += "#";
else if (isCheck())
res += "+";
}
else
{
res += hdata->piece.toStdString();
if (hdata->fromSquare != '-')
res += hdata->fromSquare;
if (isCapture())
res += "x";
res += hdata->toSquare.col();
res += hdata->toSquare.row();
if (hdata->promoted)
{
res += "=";
res += hdata->promoted->toStdString();
}
if (isCheckMate())
res += "#";
else if (isCheck())
res += "+";
}
if (hdata->comment)
res += hdata->comment->toStdString();
return res;
}
int Engine::AlphaBeta(int depth, int alpha, int beta, vector<Move>* variation, bool cannull, bool dopv)
{
#ifdef BLITZKRIEG_DEBUG
Bitset tablekey = pos.PawnKey;
if (alpha > beta || alpha < CONS_NEGINF || beta > CONS_INF)
{
cout << "info string ERROR: alpha > beta" << alpha << " " << beta << " " << ply << endl;
}
#endif
if (isDraw()) return 0;
///Quiescence
if (depth == 0)
{
int value = QuiescenceSearch(alpha, beta); //go to quiescence
/*if (value > alpha && value < beta)
PvSize = ply - 1;*/
//Table.Save(pos.TTKey,0,value,TT_EXACT,CONS_NULLMOVE);
return value;
}
nodes++;
if (nodes%CheckupNodeCount == 0)
{
checkup();
//nodes = 0;
}
///Repetition
if (ply != 0 && pos.isRepetition()) //check for repetition
{
//Table.Save(pos.TTKey,depth,0,TT_EXACT,CONS_NULLMOVE);
return 0;
}
///Probe
int probe = Table.Probe(pos.TTKey, depth, alpha, beta);
Move ttbestmove = createNullMove(pos.epsquare);
if (probe != CONS_TTUNKNOWN)
{
//cout << probe << " found " << pos.TTKey << endl;
if (ply != 0)
{
tthitcount++;
return probe;
}
/*else
{
ttbestmove = Table.getBestMove(pos.TTKey);
if (!ttbestmove.isNullMove())
{
variation->push_back(ttbestmove);
tthitcount++;
return probe;
}
}*/
}
//if (probe.avoidnull) cannull = false;
int leafevalprobe = Table.Probe(pos.TTKey, 0, alpha, beta);
if (leafevalprobe!=CONS_TTUNKNOWN
//&& leafevalprobe.entry->bound==TT_EXACT
)
{
Evaluation[ply] = leafevalprobe; //use TT probe as a better leafeval
}
else
{
if (ply > 0 && currentVariation[ply] == CONS_NULLMOVE) //if last move was a nullmove, just invert score
{
Evaluation[ply] = -Evaluation[ply-1];
assert(!cannull);
}
else
{
Evaluation[ply] = LeafEval<false>();
}
}
///Razoring
if (!dopv && ply != 0 && depth < 4 && !incheck[ply] &&
(((Evaluation[ply] + getRazorMargin(depth)) <= alpha)))
{
prunednodes++;
if (depth <= 1 && (Evaluation[ply] + getRazorMargin(3)) <= alpha)
return QuiescenceSearch(alpha, beta);
int ralpha = alpha - getRazorMargin(depth);
int v = QuiescenceSearch(ralpha, ralpha + 1);
if (v <= ralpha)
return v;
}
///Futility
if (depth < 5 && ply != 0 && !incheck[ply] && ((Evaluation[ply] - getFutilityMargin(depth)) >= beta))
{
futilitynodes++;
return (Evaluation[ply] - getFutilityMargin(depth));
}
int bound = TT_ALPHA;
/*vector<Move> dummyline;
dummyline.reserve(128);*/
/*vector<Move> lineptr;
lineptr.reserve(128);*/
vector<Move> line;
line.reserve(128);
Move m;
int score = 0;
///Null Move
bool madenullmove = false;
Bitset Pieces = pos.OccupiedSq ^ pos.Pieces[COLOR_WHITE][PIECE_PAWN] ^ pos.Pieces[COLOR_BLACK][PIECE_PAWN];
int pieceCount = popcnt(Pieces);
if (cannull && !dopv && depth >= 3 && incheck[ply] == false
&& (pieceCount>2) //side to move does not have only pawns(to avoid zugzwang)
//&& Evaluation[ply] >= beta
)
{
madenullmove = true;
//int R = depth > 5 ? 3 : 2; //dynamic depth-based reduction
int R = ((823 + 67 * depth) / 256 + std::min(max(0, Evaluation[ply] - beta) / PieceMaterial[PIECE_PAWN], 3));
m = createNullMove(pos.epsquare);
ply++;
#ifdef BLITZKRIEG_DEBUG
Bitset ttkeynull = pos.TTKey;
#endif
pos.forceMove(m);
/*bool fullnullmovesearch = true;
if (depth >= 7)
{
score = -QuiescenceSearchStandPat(-beta, -beta+1);
if (score < beta)
fullnullmovesearch = false;
}
if(fullnullmovesearch)*/
score = -AlphaBeta(max(0, depth - R), -beta, -beta+1, &line, false, false); //make a null-window search (we don't care by how much it fails high, if it does)
ply--;
pos.unmakeMove(m);
if (line.empty()!=true)
Threats[ply] = line.at(line.size() - 1);
#ifdef BLITZKRIEG_DEBUG
if (ttkeynull != pos.TTKey)
{
cout << "info string ERROR: Null TT fail" << endl;
_getch();
}
#endif
if (score >= beta)
{
//cout << "Null move cutoff " << beta << endl;
/*if (probe.avoidnull)
badavoidnull++;*/
nullcutoffs++;
return score;
}
//if (score < alpha - 100) //score is so bad, we are in danger, so increase depth
//{
// depth++;
//}
}
//futility pruning
//bool futilityprune = false;
//if (depth < 4 && !underCheck &&
// (((leafeval + FutilityMargin[depth]) <= alpha))) //futility pruning
//{
// futilitynodes++;
// futilityprune = true;
//}
//movesort(vec,depth);
bool alpharaised = false;
bool foundlegal = false;
Move alphamove = CONS_NULLMOVE;
int finalalpha = -1;
int firstalpha = -1;
//vec = pos.generateMoves();
vector<Move> vec;
vec.reserve(128);
//movegentime.Start();
//if (futilityprune)
//{
// pos.generateCaptures(vec); //search only captures in futility pruning
//}
//else
//{
pos.generateMoves(vec);
//}
//movegentime.Stop();
/*vector<Move> line;
line.reserve(128);*/
/*vector<int> scores;
scores.reserve(128);
generateCaptureScores(vec, scores);*/
if (probe==CONS_TTUNKNOWN && (dopv || Evaluation[ply] + 256 >= beta) && depth >= 2) //internal iterative deepening
{
int score = AlphaBeta(depth-2, alpha, beta, &line, false, dopv);
}
int evaldiff = ply >= 2 ? Evaluation[ply] - Evaluation[ply - 2] : 0;
vector<Move> quietmoves;
quietmoves.reserve(128);
int bestscore = CONS_NEGINF;
//int oldsortphase = SORTPHASE_NONE;
for (unsigned int i = 0;i < vec.size();i++) //search
{
line.clear();
//dummyline.clear();
//m = vec.at(i);
//int tablekey2 = pos.TTKey;
m = getHighestScoringMove(vec, i);
#ifdef BLITZKRIEG_DEBUG
if (SortPhase == SORTPHASE_NONE)
cout << "info string Sort Phase error" << endl;
#endif
int capturedpiece = m.getCapturedPiece();
int special = m.getSpecial();
int movingpiece = m.getMovingPiece();
int moveto = m.getTo();
int movefrom = m.getFrom();
int iscapture = isCapture(m);
/*int see = 0;
int evade_see = 0;
Move smallestattckr = pos.getSmallestAttacker(getOpponent(pos.turn), movefrom);
if (iscapture)
{
see = StaticExchangeEvaluation(moveto, movefrom, movingpiece, capturedpiece);
}
if (!smallestattckr.isNullMove())
{
evade_see = StaticExchangeEvaluation(movefrom, smallestattckr.getTo(), smallestattckr.getMovingPiece(), movingpiece);
}*/
//if (iscapture && depth <= 1 && see < 0)
//{ //prune bad captures at low depths
// continue;
//}
//if (depth < 8
// && !alpharaised
// && noMaterialGain(m)
// //&& !incheck[ply]
// && !incheck[ply - 1]
// && movingpiece!=PIECE_PAWN
// )
//{
// if (i >= 2+depth*depth)
// {
// continue;
// }
//}
if (!pos.makeMove(m))
{
continue;
}
//if (vec.size() == 1 || (foundlegal==false && i==vec.size()-1)) //singular extension, only 1 legal move, so extend
//{
// depth++;
//}
foundlegal = true;
ply++;
currentVariation[ply] = m;
score = 0;
int reductiondepth = 1;
///Check Extension
if (pos.underCheck(pos.turn))
{
incheck[ply] = true;
reductiondepth--;
}
else
{
incheck[ply] = false;
}
///Recapture Extension
/*if (ply > 1 && m.getTo() == currentVariation[ply - 1].getTo() && iscapture && isCapture(currentVariation[ply - 1]))
{
reductiondepth--;
}*/
//extend when capturing the last piece
/*if (isCapture(m) && getSquare2Piece(capturedpiece) != PIECE_PAWN
&& popcnt(pos.Pieces[COLOR_WHITE][PIECE_PAWN]) + popcnt(pos.Pieces[COLOR_BLACK][PIECE_PAWN]) + 2 == popcnt(pos.OccupiedSq))
{
reductiondepth -= 3;
}*/
/*if (depth < 16)
{
if (!incheck[ply - 1]
&& !incheck[ply]
&& movingpiece != PIECE_PAWN
&& noMaterialGain(m))
{
if(i > 3 + (1 << (depth-1)))
{
pos.unmakeMove(m);
incheck[ply] = false;
ply--;
continue;
}
}
}*/
//if (!dopv && depth < 4 && ((Evaluation[ply] + getSmallRazorMargin(depth)) <= alpha)) //small forward razoring
//{
// reductiondepth++;
//}
///Latemove Reduction
if (!alpharaised
//&& i >= 4
&& depth >= 4
//&& special!=PIECE_QUEEN
//&& (see < 0 || !iscapture)
&& SortPhase >= SORTPHASE_HISTORY
//&& noMaterialGain(m)
//&& (KillerMoves[0][ply].getTo() != moveto || KillerMoves[0][ply].getFrom() != movefrom)
//&& (KillerMoves[1][ply].getTo() != moveto || KillerMoves[1][ply].getFrom() != movefrom)
&& !incheck[ply]
&& !incheck[ply-1]
//&& (movingpiece!=PIECE_PAWN || getRank(getColorMirror(getOpponent(pos.turn), moveto))<6) //dont reduce pawn moves past 6th rank
//&& m!=Threats[ply]
)
{
if (evaldiff > 0)
reductiondepth += min(depth - 4, min((int)i,4));
else
reductiondepth += min(depth - 4, min((int)i+1,5));
assert((depth - reductiondepth) >= 3);
if (!dopv && HistoryScores[movingpiece][moveto] < 0) //history reduction
{
reductiondepth++;
}
if (m == Threats[ply] && reductiondepth > 0) //decrease reduction if move is a threat
{
reductiondepth = max(reductiondepth - 1, 0);
}
//if (noMaterialGain(m) && !smallestattckr.isNullMove() && evade_see < 0) //decrease reduction if move evades a capture
//{
// reductiondepth = max(reductiondepth - 1, 0);
//}
}
//if (isCapture(m) && !dopv && see > 400 && depth>=5) //prune really good captures
//{
// reductiondepth += 4;
//}
//if (alpha_counter != 0 && (depth-reductiondepth)>=3 && i>((double)alphalast_sum/alpha_counter) && capturedpiece == SQUARE_EMPTY && special == PIECE_NONE
// && !pos.underCheck(pos.turn)
// && (KillerMoves[0][ply].getTo() != m.getTo() || KillerMoves[0][ply].getFrom() != m.getFrom())
// && (KillerMoves[1][ply].getTo() != m.getTo() || KillerMoves[1][ply].getFrom() != m.getFrom())) //latemove reduction
//{
// reductiondepth += 2;
// /*reductiondepth ++;
// if (i >= 8 && depth >= 6)
// {
// reductiondepth++;
// if (i >= 12 && depth >= 9)
// reductiondepth++;
// }*/
//}
///Search
if(dopv && i>0 && depth>=3) //principal variation search
{
score = -AlphaBeta(max(depth - reductiondepth, 0), -alpha - 1, -alpha, &line, true, false);
if(score > alpha && score < beta) //check for failure
{
line.clear();
score = -AlphaBeta(depth - 1, -beta, -alpha, &line, true, true); //research
alpharaised = false;
pvresearch++;
//cout << "pv research" << endl;
}
}
else
{
score = -AlphaBeta(max(depth - reductiondepth,0), -beta, -alpha, &line, true, dopv);
//cout << "latemove" << endl;
if(score > alpha && score < beta && reductiondepth>1)
{
line.clear();
score = -AlphaBeta(depth - 1, -beta, -alpha, &line, true, dopv);
latemoveresearch++;
}
}
currentVariation[ply] = CONS_NULLMOVE;
incheck[ply] = false;
ply--;
pos.unmakeMove(m);
assert(score > CONS_NEGINF && score < CONS_INF);
assert(score >= CONS_MATED && score <= -CONS_MATED);
if(score>=beta)
{
if(noMaterialGain(m))
{
//if(Table.getBestMove(pos.TTKey)!=m) //dont store hash move as a killer
setKiller(m, depth, score);
int bonus = depth*depth;
HistoryScores[movingpiece][m.getTo()] += bonus;
if (HistoryScores[movingpiece][m.getTo()] > 200000) //prevent overflow of history values
{
for (int i = 0;i < 6;i++)
{
for (int j = 0;j < 64;j++)
{
HistoryScores[i][j] /= 2;
}
}
}
for (int i = 0;i < quietmoves.size();i++)
{
/*if(HistoryScores[quietmoves.at(i).getMovingPiece()][quietmoves.at(i).getTo()] <= bonus)
HistoryScores[quietmoves.at(i).getMovingPiece()][quietmoves.at(i).getTo()] = 0;
else*/
HistoryScores[quietmoves.at(i).getMovingPiece()][quietmoves.at(i).getTo()] -= bonus;
}
}
Table.Save(pos.TTKey, depth, score, TT_BETA, m);
#ifdef BLITZKRIEG_STATS
betacutoff_counter++;
betacutoff_sum += i+1;
if (i == 0)
firstbetacutoffcount++;
#endif
return score; //fail soft beta cutoff
}
else if(score>bestscore)
{
bestscore = score;
if (score > alpha)
{
bound = TT_EXACT;
alpha = score;
alpharaised = true;
alphamove = m;
*variation = line;
if (noMaterialGain(m))
HistoryScores[movingpiece][m.getTo()] += depth;
#ifdef BLITZKRIEG_STATS
if (firstalpha == -1)
{
firstalpha = i;
}
finalalpha = i;
#endif
}
}
if (noMaterialGain(m))
{
quietmoves.push_back(m);
}
}
if(!foundlegal)
{
//if(futilityprune)
//{
// //movegentime.Start();
// vec.clear();
// pos.generateMoves(vec);
// //movegentime.Stop();
// int flag = 1;
// for(int i = 0;i<vec.size();i++)
// {
// if(pos.makeMove(m))
// {
// unmakeMove(m);
// flag = 0;
// break;
// }
// }
// if(flag)
// {
// if(pos.underCheck(pos.turn))
// {
// return CONS_MATED-ply;
// }
// else
// {
// return CONS_DRAW;
// }
// }
//}
//else
{
if(pos.underCheck(pos.turn))
{
return CONS_MATED+ply;
}
else
{
return CONS_DRAW;
}
}
}
if(!alphamove.isNullMove())
{
variation->push_back(alphamove);
//if(dopv)
// PrincipalVariation[ply] = alphamove;
/*if (depth == 1)
{
PvSize = ply;
PvPly = ply;
}*/
/*else if (ply == PvPly - 1)
{
PrincipalVariation[ply] = alphamove;
PvPly = ply;
}*/
//HistoryScores[alphamove.getFrom()][alphamove.getTo()] += depth+finalalpha;
#ifdef BLITZKRIEG_STATS
alpha_counter++;
alphalast_sum += (finalalpha + 1);
alphafirst_sum += (firstalpha + 1);
#endif
}
Table.Save(pos.TTKey, depth, bestscore, bound, alphamove);
/*if (ply == 0)
{
cout << "info string Stored: " << alphamove.toString() << " " << bound << " " << depth << endl;
}*/
#ifdef BLITZKRIEG_DEBUG
if (pos.PawnKey != tablekey)
{
cout << "info string ERROR: Pawn TT key doesnt match" << endl;
}
#endif
return bestscore;
}
