bool ProofUtil::ShrinkProof(bitset_t& proof, const StoneBoard& board,
HexColor loser, const ICEngine& ice)
{
StoneBoard brd(board.Width(), board.Height());
PatternState pastate(brd);
Groups groups;
// Give loser all cells outside proof
bitset_t cells_outside_proof = (~proof & brd.Const().GetCells());
brd.AddColor(loser, cells_outside_proof);
// Give winner only his stones inside proof;
HexColor winner = !loser;
brd.AddColor(winner, board.GetPlayed(winner) & proof);
pastate.Update();
GroupBuilder::Build(brd, groups);
// Compute fillin and remove captured cells from the proof
InferiorCells inf;
ice.ComputeFillin(loser, groups, pastate, inf,
HexColorSetUtil::Only(loser));
HexAssert(inf.Captured(winner).none());
bitset_t filled = inf.Dead() | inf.Captured(loser);
bitset_t shrunk_proof = proof - filled;
bool shrunkTheProof = shrunk_proof.count() < proof.count();
proof = shrunk_proof;
return shrunkTheProof;
}
void DfpnSolver::DeleteChildren(DfpnChildren& children,
std::vector<DfpnData>& childrenData,
bitset_t deleteChildren) const
{
HexAssert(children.Size() == childrenData.size());
bitset_t deleted;
std::vector<HexPoint>::iterator it1 = children.m_children.begin();
std::vector<DfpnData>::iterator it2 = childrenData.begin();
while (it1 != children.m_children.end())
{
HexAssert(it2 != childrenData.end());
if (deleteChildren.test(*it1))
{
HexAssert(!deleted.test(*it1));
deleted.set(*it1);
it1 = children.m_children.erase(it1);
it2 = childrenData.erase(it2);
}
else
{
++it1;
++it2;
}
}
HexAssert(children.Size() > 0);
HexAssert(children.Size() == childrenData.size());
HexAssert(deleteChildren == deleted);
}
//
// *b*it *ar*ithmetics (BAR)
//
template<class T> inline void bar(
const Perm_matrix<T>& pmat, //matrix of predefined permutations
const bitset_t& b, //bitset aka dummy coded data
std::valarray<T>& res) //results are written into res
{
assert (b.size() == pmat.bitMat_.front().size());
assert (res.size() == pmat.bitMat_.size());
for (size_t i=0; i<res.size(); i++) {
res[i] = (b & pmat.bitMat_[i]).count();
}
}
HexPoint BenzenePlayer::CheckEndgame(HexBoard& brd, HexColor color,
bitset_t& consider, double& score)
{
if (EndgameUtil::IsDeterminedState(brd, color, score))
return EndgameUtil::PlayDeterminedState(brd, color);
else
{
consider = EndgameUtil::MovesToConsider(brd, color);
BenzeneAssert(consider.any());
}
score = 0;
if (consider.count() == 1 && !m_search_singleton)
{
HexPoint move = static_cast<HexPoint>
(BitsetUtil::FindSetBit(consider));
LogInfo() << "Mustplay is singleton!\n";
return move;
}
return INVALID_POINT;
}
inline bool StoneBoard::IsPlayed(HexPoint cell) const
{
BenzeneAssert(Const().IsValid(cell));
return m_played.test(cell);
}
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;
}
/** Does a 1-ply search.
For each move in the consider set, if the move is a win, returns
true and the move. If the move is a loss, prune it out of the
consider set if there are non-losing moves in the consider set.
If all moves are losing, perform no pruning, search will resist.
Returns true if there is a win, false otherwise.
@todo Is it true that MoHex will resist in the strongest way
possible?
*/
bool MoHexPlayer::PerformPreSearch(HexBoard& brd, HexColor color,
bitset_t& consider, double maxTime,
PointSequence& winningSequence)
{
bitset_t losing;
HexColor other = !color;
PointSequence seq;
bool foundWin = false;
SgTimer elapsed;
Resistance resist;
resist.Evaluate(brd);
std::vector<HexPoint> moves;
SortConsiderSet(consider, resist, moves);
for (std::size_t i = 0; i < moves.size() && !foundWin; ++i)
{
if (elapsed.GetTime() > maxTime)
{
LogInfo() << "PreSearch: max time reached "
<< '(' << i << '/' << moves.size() << ").\n";
break;
}
brd.PlayMove(color, moves[i]);
seq.push_back(moves[i]);
if (EndgameUtil::IsLostGame(brd, other)) // Check for winning move
{
winningSequence = seq;
foundWin = true;
}
else if (EndgameUtil::IsWonGame(brd, other))
losing.set(moves[i]);
seq.pop_back();
brd.UndoMove();
}
// Abort if we found a one-move win
if (foundWin)
return true;
// Backing up cannot cause this to happen, right?
BenzeneAssert(!EndgameUtil::IsDeterminedState(brd, color));
// Use the backed-up ice info to shrink the moves to consider
if (m_backup_ice_info)
{
bitset_t new_consider
= EndgameUtil::MovesToConsider(brd, color) & consider;
if (new_consider.count() < consider.count())
{
consider = new_consider;
LogFine() << "$$$$$$ new moves to consider $$$$$$"
<< brd.Write(consider) << '\n';
}
}
// Subtract any losing moves from the set we consider, unless all of them
// are losing (in which case UCT search will find which one resists the
// loss well).
if (losing.any())
{
if (BitsetUtil::IsSubsetOf(consider, losing))
LogInfo() << "************************************\n"
<< " All UCT root children are losing!!\n"
<< "************************************\n";
else
{
LogFine() << "Removed losing moves: " << brd.Write(losing) << '\n';
consider = consider - losing;
}
}
BenzeneAssert(consider.any());
LogInfo() << "Moves to consider:\n" << brd.Write(consider) << '\n';
return false;
}
inline bool Group::IsMember(HexPoint point) const
{
return m_members.test(point);
}
inline std::size_t Group::Size() const
{
/** @todo Cache group size for speed? */
return m_members.count();
}