/** Finds inferior cells, builds vcs. Sets moves to consider to all
empty cells. If fillin causes terminal state, sets
m_fillinCausedWin to true and recomputes fillin/vcs with ice
temporarily turned off (so it can pass the players a non-empty
consider set).
*/
HexPoint BenzenePlayer::InitSearch(HexBoard& brd, HexColor color,
bitset_t& consider, double& score)
{
// Resign if the game is already over
Groups groups;
GroupBuilder::Build(brd.GetPosition(), groups);
if (groups.IsGameOver())
{
score = IMMEDIATE_LOSS;
return RESIGN;
}
StoneBoard original(brd.GetPosition());
brd.ComputeAll(color);
m_fillinCausedWin = false;
m_fillinWinner = EMPTY;
if (brd.GetGroups().IsGameOver())
{
// Fillin caused win, remove and re-compute without ice.
m_fillinCausedWin = true;
m_fillinWinner = brd.GetGroups().GetWinner();
LogInfo() << "Captured cells caused win! Removing...\n";
brd.GetPosition().SetPosition(original);
bool oldUseIce = brd.UseICE();
brd.SetUseICE(false);
brd.ComputeAll(color);
brd.SetUseICE(oldUseIce);
BenzeneAssert(!brd.GetGroups().IsGameOver());
}
consider = brd.GetPosition().GetEmpty();
score = 0;
return INVALID_POINT;
}
bitset_t ProofUtil::InitialProofForOpponent(const HexBoard& brd,
HexColor toPlay)
{
// Add opponent played stones and deduction set.
const InferiorCells& inf = brd.GetInferiorCells();
bitset_t proof = brd.GetPosition().GetPlayed(!toPlay);
proof |= inf.DeductionSet(!toPlay);
// Add all semi-connections from the mustplay.
const VCList& lst = brd.Cons(!toPlay).GetList(VC::SEMI,
HexPointUtil::colorEdge1(!toPlay),
HexPointUtil::colorEdge2(!toPlay));
const bool useGreedy = brd.Builder().Parameters().use_greedy_union;
proof |= useGreedy ? lst.getGreedyUnion() : lst.getUnion();
// Add reversable reversers.
// The carriers do NOT need to be included in the proof, since
// they are captured by the (losing) player, not his opponent (for
// whom we are building the proof set).
// TODO: Currently, we just add the first reverser: we should see
// if any reverser is already in the proof, since then we wouldn't
// need to add one.
for (BitsetIterator p(inf.Reversible()); p; ++p)
{
const std::set<HexPoint>& reversers = inf.Reversers(*p);
proof.set(*reversers.begin());
}
// Add vulnerable killers and their carriers.
// TODO: Currently, we just add the first killer: we should see if
// any killer is already in the proof, since then we wouldn't need
// to add one.
for (BitsetIterator p(inf.Vulnerable()); p; ++p)
{
const std::set<VulnerableKiller>& killers = inf.Killers(*p);
proof.set((*killers.begin()).killer());
proof |= ((*killers.begin()).carrier());
}
return proof;
}
bool EndgameUtil::IsLostGame(const HexBoard& brd, HexColor color,
bitset_t& proof)
{
if (brd.GetGroups().GetWinner() == !color)
{
proof = StonesInProof(brd, !color);
return true;
}
VC vc;
if (brd.Cons(!color).SmallestVC(HexPointUtil::colorEdge1(!color),
HexPointUtil::colorEdge2(!color),
VC::FULL, vc))
{
proof = vc.Carrier() | StonesInProof(brd, !color);
return true;
}
if (ComputeConsiderSet(brd, color).none())
{
proof = brd.GetPosition().GetEmpty() | StonesInProof(brd, !color);
return true;
}
return false;
}
bitset_t ProofUtil::MaximumProofSet(const HexBoard& brd, HexColor toPlay)
{
return brd.GetPosition().GetEmpty()
| brd.GetPosition().GetPlayed(toPlay)
| brd.GetInferiorCells().DeductionSet(toPlay);
}
bool Decompositions::Find(const HexBoard& brd, HexColor color,
bitset_t& captured)
{
// If game is over or decided, don't do any work.
HexPoint edge1 = HexPointUtil::colorEdge1(color);
HexPoint edge2 = HexPointUtil::colorEdge2(color);
const VCSet& cons = brd.Cons(color);
if (brd.GetGroups().IsGameOver() || cons.Exists(edge1, edge2, VC::FULL))
{
captured.reset();
return false;
}
/** Compute neighbouring groups of opposite color.
NOTE: Assumes that edges that touch are adjacent. See
ConstBoard for more details.
*/
PointToBitset adjTo;
PointToBitset adjByMiai;
ComputeAdjacentByMiai(brd, adjByMiai);
for (GroupIterator g(brd.GetGroups(), color); g; ++g)
{
bitset_t opptNbs = adjByMiai[g->Captain()]
| (g->Nbs() & brd.GetPosition().GetColor(!color));
if (opptNbs.count() >= 2)
adjTo[g->Captain()] = opptNbs;
}
// The two color edges are in the list. If no other groups are, then quit.
BenzeneAssert(adjTo.size() >= 2);
if (adjTo.size() == 2)
{
captured.reset();
return false;
}
// Compute graph representing board from color's perspective.
PointToBitset graphNbs;
GraphUtil::ComputeDigraph(brd.GetGroups(), color, graphNbs);
// Find (ordered) pairs of color groups that are VC-connected and have at
// least two adjacent opponent groups in common.
PointToBitset::iterator g1, g2;
for (g1 = adjTo.begin(); g1 != adjTo.end(); ++g1) {
for (g2 = adjTo.begin(); g2 != g1; ++g2) {
if ((g1->second & g2->second).count() < 2) continue;
if (!cons.Exists(g1->first, g2->first, VC::FULL)) continue;
// This is such a pair, so at least one of the two is not an edge.
// Find which color edges are not equal to either of these groups.
BenzeneAssert(!HexPointUtil::isEdge(g1->first) ||
!HexPointUtil::isEdge(g2->first));
bool edge1Free = (g1->first != edge1 && g2->first != edge1);
bool edge2Free = (g1->first != edge2 && g2->first != edge2);
// Find the set of empty cells bounded by these two groups.
bitset_t stopSet = graphNbs[g1->first] | graphNbs[g2->first];
bitset_t decompArea;
decompArea.reset();
if (edge1Free)
decompArea |= GraphUtil::BFS(edge1, graphNbs, stopSet);
if (edge2Free)
decompArea |= GraphUtil::BFS(edge2, graphNbs, stopSet);
decompArea.flip();
decompArea &= brd.GetPosition().GetEmpty();
// If the pair has a VC confined to these cells, then we have
// a decomposition - return it.
const VCList& vl = cons.GetList(VC::FULL, g1->first, g2->first);
for (VCListConstIterator it(vl); it; ++it)
{
if (BitsetUtil::IsSubsetOf(it->Carrier(), decompArea))
{
captured = it->Carrier();
return true;
}
}
}
}
// No combinatorial decomposition with a VC was found.
captured.reset();
return false;
}
HexPoint MoHexPlayer::Search(const HexState& state, const Game& game,
HexBoard& brd, const bitset_t& given_to_consider,
double maxTime, double& score)
{
BenzeneAssert(!brd.GetGroups().IsGameOver());
HexColor color = state.ToPlay();
SgTimer totalElapsed;
PrintParameters(color, maxTime);
// Do presearch and abort if win found. Allow it to take 20% of
// total time.
SgTimer timer;
bitset_t consider = given_to_consider;
PointSequence winningSequence;
if (m_performPreSearch && PerformPreSearch(brd, color, consider,
maxTime * 0.2, winningSequence))
{
LogInfo() << "Winning sequence found before UCT search!\n"
<< "Sequence: " << winningSequence[0] << '\n';
score = IMMEDIATE_WIN;
return winningSequence[0];
}
timer.Stop();
LogInfo() << "Time for PreSearch: " << timer.GetTime() << "s\n";
maxTime -= timer.GetTime();
maxTime = std::max(1.0, maxTime);
// Create the initial state data
MoHexSharedData data(m_search.FillinMapBits());
data.gameSequence = game.History();
data.rootState = HexState(brd.GetPosition(), color);
data.rootConsider = consider;
// Reuse the old subtree
SgUctTree* initTree = 0;
if (m_reuse_subtree)
{
MoHexSharedData oldData(m_search.SharedData());
initTree = TryReuseSubtree(oldData, data);
if (!initTree)
LogInfo() << "No subtree to reuse.\n";
}
m_search.SetSharedData(data);
brd.GetPatternState().ClearPatternCheckStats();
int old_radius = brd.GetPatternState().UpdateRadius();
brd.GetPatternState().SetUpdateRadius(m_search.TreeUpdateRadius());
// Do the search
std::vector<SgMove> sequence;
std::vector<SgMove> rootFilter;
m_search.SetBoard(brd);
score = m_search.Search(m_max_games, maxTime, sequence,
rootFilter, initTree, 0);
brd.GetPatternState().SetUpdateRadius(old_radius);
// Output stats
std::ostringstream os;
os << '\n';
#if COLLECT_PATTERN_STATISTICS
{
MoHexState& thread0
= dynamic_cast<MoHexState&>(m_search.ThreadState(0));
MoHexPolicy* policy = dynamic_cast<MoHexPolicy*>(thread0.Policy());
if (policy)
os << policy->DumpStatistics() << '\n';
}
#endif
os << "Elapsed Time " << totalElapsed.GetTime() << "s\n";
m_search.WriteStatistics(os);
os << "Score " << std::setprecision(2) << score << "\n"
<< "Sequence ";
for (std::size_t i = 0; i < sequence.size(); i++)
os << " " << MoHexUtil::MoveString(sequence[i]);
os << '\n';
LogInfo() << os.str() << '\n';
#if 0
if (m_save_games)
{
std::string filename = "uct-games.sgf";
uct.SaveGames(filename);
LogInfo() << "Games saved in '" << filename << "'.\n";
}
#endif
// Return move recommended by MoHexSearch
if (sequence.size() > 0)
return static_cast<HexPoint>(sequence[0]);
// It is possible that MoHexSearch did only 1 simulation (probably
// because it ran out of time to do more); in this case, the move
// sequence is empty and so we give a warning and return a random
// move.
LogWarning() << "**** MoHexSearch returned empty sequence!\n"
<< "**** Returning random move!\n";
return BoardUtil::RandomEmptyCell(brd.GetPosition());
}
