void AlignmentGraph::ExtractMinimalRules(const Options &options)
{
// Determine which nodes are frontier nodes.
std::set<Node *> frontierSet;
ComputeFrontierSet(m_root, options, frontierSet);
// Form the minimal frontier graph fragment rooted at each frontier node.
std::vector<Subgraph> fragments;
fragments.reserve(frontierSet.size());
for (std::set<Node *>::iterator p(frontierSet.begin());
p != frontierSet.end(); ++p) {
Node *root = *p;
Subgraph fragment = ComputeMinimalFrontierGraphFragment(root, frontierSet);
assert(!fragment.IsTrivial());
// Can it form an SCFG rule?
// FIXME Does this exclude non-lexical unary rules?
if (root->GetType() == TREE && !root->GetSpan().empty()) {
root->AddRule(new Subgraph(fragment));
}
}
}
