/** Extract the PV starting from pos, using hash entries, both exact scores and bounds. */
public string extractPV(Position pos)
{
string ret = "";
pos = new Position(pos); // To avoid modifying the input parameter
bool first = true;
TTEntry ent = probe(pos.historyHash());
UndoInfo ui = new UndoInfo();
List<ulong> hashHistory = new List<ulong>();
bool repetition = false;
while (ent.type != TTEntry.T_EMPTY) {
string type = "";
if (ent.type == TTEntry.T_LE) {
type = "<";
} else if (ent.type == TTEntry.T_GE) {
type = ">";
}
Move m = new Move(0,0,0);
ent.getMove(m);
MoveGen MG = new MoveGen();
MoveGen.MoveList moves = MG.pseudoLegalMoves(pos);
MoveGen.RemoveIllegal(pos, moves);
bool contains = false;
for (int mi = 0; mi < moves.size; mi++)
if (moves.m[mi].equals(m)) {
contains = true;
break;
}
if (!contains)
break;
string moveStr = TextIO.moveTostring(pos, m, false);
if (repetition)
break;
if (!first) {
ret += " ";
}
ret += type + moveStr;
pos.makeMove(m, ui);
if (hashHistory.Contains(pos.zobristHash())) {
repetition = true;
}
hashHistory.Add(pos.zobristHash());
ent = probe(pos.historyHash());
first = false;
}
return ret;
}
/**
* Extract a list of PV moves, starting from "rootPos" and first move "m".
*/
public List<Move> extractPVMoves(Position rootPos, Move m)
{
Position pos = new Position(rootPos);
m = new Move(m);
List<Move> ret = new List<Move>();
UndoInfo ui = new UndoInfo();
List<ulong> hashHistory = new List<ulong>();
MoveGen moveGen = new MoveGen();
while (true) {
ret.Add(m);
pos.makeMove(m, ui);
if (hashHistory.Contains(pos.zobristHash())) {
break;
}
hashHistory.Add(pos.zobristHash());
TTEntry ent = probe(pos.historyHash());
if (ent.type == TTEntry.T_EMPTY) {
break;
}
m = new Move(0,0,0);
ent.getMove(m);
MoveGen.MoveList moves = moveGen.pseudoLegalMoves(pos);
MoveGen.RemoveIllegal(pos, moves);
bool contains = false;
for (int mi = 0; mi < moves.size; mi++)
if (moves.m[mi].equals(m)) {
contains = true;
break;
}
if (!contains)
break;
}
return ret;
}
