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Optimized Graph::from_nfa #3

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36 changes: 25 additions & 11 deletions src/graph.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,9 @@
#include <spot/twaalgos/hoa.hh>
#include <spot/twaalgos/translate.hh>

#include <boost/unordered_map.hpp>
#include <boost/unordered_set.hpp>

// Thanks to:
// https://helloacm.com/the-union-find-disjoint-set-implementation-in-java/
class UnionFind {
Expand Down Expand Up @@ -248,10 +251,11 @@ Graph Graph::from_att_file(const std::string& filename)
Graph Graph::from_nfa(const std::set<State>& q0n, const std::set<State>& Fn,
const NFADelta& dn)
{
using StateSubset = std::set<State>;
// StateSubset must be sorted
using StateSubset = std::vector<State>;

// 2^{Qn} -> Qd
std::map<StateSubset, State> st_map;
boost::unordered_map<StateSubset, State> st_map;
// df
DFADelta df;
// Ff
Expand All @@ -277,37 +281,47 @@ Graph Graph::from_nfa(const std::set<State>& q0n, const std::set<State>& Fn,
spdlog::info("{}", ss.str());
};
*/
StateSubset q0nVec = std::vector<State>{q0n.begin(), q0n.end()};
std::sort(q0nVec.begin(), q0nVec.end());

std::set<StateSubset> visited;
std::queue<StateSubset> que;
que.push(q0n);
que.push(q0nVec);
const auto visited = [&] (const StateSubset& qs) -> bool {
auto it = st_map.find(qs);
return it != st_map.end() && std::get<1>(df.at(it->second)) != -1;
};
while (!que.empty()) {
StateSubset qs = que.front();
que.pop();
if (visited.contains(qs))
if (visited(qs))
continue;

StateSubset qs0, qs1;
for (State q : qs) {
auto&& [q_, dst0, dst1] = dn.at(q);
qs0.insert(dst0.begin(), dst0.end());
qs1.insert(dst1.begin(), dst1.end());
qs0.insert(qs0.end(), dst0.begin(), dst0.end());
qs1.insert(qs1.end(), dst1.begin(), dst1.end());
}
std::sort(qs0.begin(), qs0.end());
qs0.erase(std::unique(qs0.begin(), qs0.end()), qs0.end());
std::sort(qs1.begin(), qs1.end());
qs1.erase(std::unique(qs1.begin(), qs1.end()), qs1.end());
bool final = std::any_of(qs.begin(), qs.end(),
[&Fn](size_t q) { return Fn.contains(q); });

State qsd = get_or_create_state(qs), qs0d = get_or_create_state(qs0),
qs1d = get_or_create_state(qs1);
df.at(qsd) = std::make_tuple(qsd, qs0d, qs1d);

visited.insert(qs);
if (final)
Ff.insert(qsd);
que.push(qs0);
que.push(qs1);
if (!visited(qs0))
que.push(qs0);
if (!visited(qs1))
que.push(qs1);
}

return Graph{get_or_create_state(q0n), Ff, df};
return Graph{get_or_create_state(q0nVec), Ff, df};
}

Graph Graph::from_ltl_formula(const std::string& formula, size_t var_size,
Expand Down