void GoAutoBook::TruncateByDepth(int depth, GoAutoBookState& state,
GoAutoBook& other,
std::set<SgHashCode>& seen) const
{
if (seen.count(state.GetHashCode()))
return;
SgBookNode node;
if (! Get(state, node))
return;
seen.insert(state.GetHashCode());
if (depth == 0)
{
// Set this node to be a leaf: copy its heuristic value into
// its propagated value and set count to 0.
node.m_count = 0;
node.m_priority = SgBookNode::LEAF_PRIORITY;
node.m_value = node.m_heurValue;
other.Put(state, node);
return;
}
other.Put(state, node);
if (node.IsLeaf() || node.IsTerminal())
return;
for (GoBoard::Iterator it(state.Board()); it; ++it)
{
if (state.Board().IsLegal(*it))
{
state.Play(*it);
TruncateByDepth(depth - 1, state, other, seen);
state.Undo();
}
}
}
SgMove GoAutoBook::FindBestChild(GoAutoBookState& state) const
{
std::size_t bestCount = 0;
SgMove bestMove = SG_NULLMOVE;
SgMove bestIgnoredMove = SG_NULLMOVE;
float bestScore = 100.0f;
float bestIgnoredMoveScore = 100.0f;
SgBookNode node;
// Check for forced moves first
// Note this will check for forced moves even if the current
// state is not in the book.
for (GoBoard::Iterator it(state.Board()); it; ++it)
{
if (state.Board().IsLegal(*it))
{
state.Play(*it);
if (m_forced.count(state.GetHashCode()) > 0)
{
SgDebug() << "Playing forced move "
<< SgWritePoint(*it) << '\n';
return *it;
}
state.Undo();
}
}
if (! Get(state, node))
return SG_NULLMOVE;
if (node.IsLeaf())
return SG_NULLMOVE;
for (GoBoard::Iterator it(state.Board()); it; ++it)
{
if (state.Board().IsLegal(*it))
{
state.Play(*it);
if (m_disabled.count(state.GetHashCode()) > 0)
SgDebug() << "Ignoring disabled move "
<< SgWritePoint(*it) << '\n';
// NOTE: Terminal nodes aren't supported at this time, so
// we ignore them here.
else if ( Get(state, node)
&& ! node.IsTerminal()
)
{
if (node.m_count >= m_param.m_usageCountThreshold)
{
if (m_param.m_selectType == GO_AUTOBOOK_SELECT_COUNT)
{
// Select by count, tiebreak by value.
if (node.m_count > bestCount)
{
bestCount = node.m_count;
bestMove = *it;
bestScore = node.m_value;
}
// NOTE: do not have access to inverse function,
// so we're minimizing here as a temporary solution.
else if (node.m_count == bestCount
&& node.m_value < bestScore)
{
bestMove = *it;
bestScore = node.m_value;
}
}
else if (m_param.m_selectType == GO_AUTOBOOK_SELECT_VALUE)
{
// NOTE: do not have access to inverse function,
// so we're minimizing here as a temporary solution.
if (node.m_value < bestScore)
{
bestMove = *it;
bestScore = node.m_value;
}
}
}
else // node.m_count < m_param.m_usageCountThreshold
if ( m_param.m_selectType == GO_AUTOBOOK_SELECT_VALUE
&& node.m_value < bestIgnoredMoveScore
)
{
bestIgnoredMove = *it;
bestIgnoredMoveScore = node.m_value;
}
}
state.Undo();
}
}
if (bestMove != SG_NULLMOVE && bestIgnoredMoveScore < bestScore)
{
SgDebug() << "Ignoring autobook move "
<< SgWritePoint(bestMove)
<< " since best ignored inverse value "
<< std::setprecision(5)
<< bestIgnoredMoveScore
<< " of move "
<< SgWritePoint(bestIgnoredMove)
<< " is better than best value above usage threshold "
<< bestScore << '\n';
return SG_NULLMOVE;
}
return bestMove;
}
void GoAutoBook::Put(const GoAutoBookState& state, const SgBookNode& node)
{
m_data[state.GetHashCode()] = node;
}
