/** Return a string describing all book moves. */
public string getAllBookMoves(Position pos)
{
string ret = "";
List<BookEntry> bookMoves = bookMap[pos.zobristHash()];
if (bookMoves != null) {
BookEntry be;
for (int i = 0; i < bookMoves.Count; i++) {
be = bookMoves[i];
string moveStr = TextIO.moveTostring(pos, be.move, false);
ret = ret + (moveStr + "(" + be.count.ToString() + ") ");
}
}
return ret;
}
/** Return a random book move for a position, or null if out of book. */
public Move getBookMove(Position pos)
{
long t0 = SystemHelper.currentTimeMillis();
Random rndGen = new Random((int)t0);
ulong key = pos.zobristHash();
bool iskey = bookMap.ContainsKey(key);
List<BookEntry> bookMoves = (iskey ? bookMap[key] : null);
if (bookMoves == null) {
return null;
}
MoveGen.MoveList legalMoves = new MoveGen().pseudoLegalMoves(pos);
MoveGen.RemoveIllegal(pos, legalMoves);
int sum = 0;
for (int i = 0; i < bookMoves.Count; i++) {
BookEntry be = bookMoves[i];
bool contains = false;
for (int mi = 0; mi < legalMoves.size; mi++)
if (legalMoves.m[mi].equals(be.move)) {
contains = true;
break;
}
if (!contains) {
// If an illegal move was found, it means there was a hash collision.
return null;
}
sum += getWeight(bookMoves[i].count);
}
if (sum <= 0) {
return null;
}
int rnd = rndGen.Next(sum);
sum = 0;
for (int i = 0; i < bookMoves.Count; i++) {
sum += getWeight(bookMoves[i].count);
if (rnd < sum) {
return bookMoves[i].move;
}
}
// Should never get here
throw new RuntimeException();
}
/** 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;
}
/** Check if a draw claim is allowed, possibly after playing "move".
* @param move The move that may have to be made before claiming draw.
* @return The draw string that claims the draw, or empty string if draw claim not valid.
*/
private string canClaimDraw(Position pos, ulong[] posHashList, int posHashListSize, Move move)
{
string drawStr = "";
if (Search.canClaimDraw50(pos)) {
drawStr = "draw 50";
} else if (Search.canClaimDrawRep(pos, posHashList, posHashListSize, posHashListSize)) {
drawStr = "draw rep";
} else {
string strMove = TextIO.moveTostring(pos, move, false);
posHashList[posHashListSize++] = pos.zobristHash();
UndoInfo ui = new UndoInfo();
pos.makeMove(move, ui);
if (Search.canClaimDraw50(pos)) {
drawStr = "draw 50 " + strMove;
} else if (Search.canClaimDrawRep(pos, posHashList, posHashListSize, posHashListSize)) {
drawStr = "draw rep " + strMove;
}
pos.unMakeMove(move, ui);
}
return drawStr;
}
/** Add a move to a position in the opening book. */
private void addToBook(Position pos, Move moveToAdd)
{
ulong key = pos.zobristHash();
bool iskey = bookMap.ContainsKey(key);
List<BookEntry> ent = (iskey ? bookMap[key] : null );
if (ent == null) {
ent = new List<BookEntry>();
bookMap.Add( pos.zobristHash(), ent);
}
for (int i = 0; i < ent.Count; i++) {
BookEntry be = ent[i];
if (be.move.equals(moveToAdd)) {
be.count++;
return;
}
}
BookEntry be2 = new BookEntry(moveToAdd);
ent.Add(be2);
numBookMoves++;
}