std::vector<int> LevelInverseOrdering::computeVertexOrder(const InstancePtr& instance, const HTDDecompositionPtr& decomposition) const {
const htd::ConstCollection<htd::vertex_t> vertices = instance->hypergraph->internalGraph().vertices();
std::vector<htd::vertex_t> verticesSorted(vertices.begin(), vertices.end());
std::sort(verticesSorted.begin(), verticesSorted.end(), [instance] (htd::vertex_t x1, htd::vertex_t x2) -> bool {
int x1Level = htd::accessLabel<int>(instance->hypergraph->internalGraph().vertexLabel("level", x1));
int x2Level = htd::accessLabel<int>(instance->hypergraph->internalGraph().vertexLabel("level", x2));
if (x1Level > x2Level) {
return true; // return true if x1 should be ordered before x2 (ie x1 level is greater than x2 level)
} else if (x1Level == x2Level) {
return (x1 < x2); // for same level, keep instance ordering
}
return false;
});
std::vector<int> orderingIndex(instance->hypergraph->vertexCount() + 1); // "0" vertex is skipped by HTD
for (const auto& vertexId : instance->hypergraph->internalGraph().vertices()) {
int index = std::find(verticesSorted.begin(), verticesSorted.end(), vertexId) - verticesSorted.begin();
orderingIndex[vertexId] = index;
}
return orderingIndex;
}
htd::Hyperedge::Hyperedge(htd::id_t id, const htd::ConstCollection<htd::vertex_t> & elements) : written_(true), id_(id), elements_(std::make_shared<std::vector<htd::vertex_t>>(elements.begin(), elements.end()))
{
}