def bfs(self, i, j):
if (i, j) in self.negative_visited_in_kron:
return LabelGraph(self.graph_size)
if (i, j) in self.visited_pairs_in_kron:
bogus_result = LabelGraph(self.graph_size)
bogus_result.is_empty = False
return bogus_result
self.visited_pairs_in_kron.add((i, j))
result_graph = LabelGraph(self.graph_size)
for k in self.kron[i]: # k = (vertex, True)
graph_i = i % self.graph_size
graph_k = k[0] % self.graph_size
rsa_i = i // self.graph_size
rsa_k = k[0] // self.graph_size
left = LabelGraph(self.graph_size)
for label in self.rsa.labels:
if self.rsa[label].get(rsa_i, rsa_k, default=False):
if label in self.rsa.nonterminals:
left += self.get_paths(graph_i, graph_k, label)
else:
if label not in left.matrices:
left[label] = Matrix.sparse(
BOOL, self.graph_size, self.graph_size)
left[label][graph_i, graph_k] = True
if left.is_empty:
continue
right = LabelGraph(self.graph_size)
if k[0] != j:
right = self.bfs(k[0], j)
else:
right.is_empty = False
if right.is_empty:
continue
result_graph += left + right
if result_graph.is_empty:
self.negative_visited_in_kron.add((i, j))
self.visited_pairs_in_kron.remove((i, j))
return result_graph
def get_paths(self, start, finish, nonterm):
if (start, finish, nonterm) in self.solved_triplets:
bogus_result = LabelGraph(self.graph_size)
bogus_result.is_empty = False
return bogus_result
self.solved_triplets.add((start, finish, nonterm))
result = LabelGraph(self.graph_size)
start_state = self.rsa.start_state[nonterm]
for finish_state in self.rsa.finish_states[nonterm]:
result += self.bfs(start_state * self.graph_size + start,
finish_state * self.graph_size + finish)
self.solved_triplets.remove((start, finish, nonterm))
return result