Concept graph::adjacency_list does not require that vertex_id_t<G> be default-constructible. However, views::incidence (which is constrained with graph::adjacency_list) uses default construction:
https://github.com/stdgraph/graph-v2/blob/master/include/graph/views/incidence.hpp#L83
This should be fixed in one or the other way:
- Add default-constructibility to the concept
- Use
std::optional in the implementation instead of using a default-constructed value.
I personally do not like the idea of requiring default values. But if this would make the algorithm slightly faster, it is not a problem to come up with a default-constructed ID.
Concept
graph::adjacency_listdoes not require thatvertex_id_t<G>be default-constructible. However,views::incidence(which is constrained withgraph::adjacency_list) uses default construction:https://github.com/stdgraph/graph-v2/blob/master/include/graph/views/incidence.hpp#L83
This should be fixed in one or the other way:
std::optionalin the implementation instead of using a default-constructed value.I personally do not like the idea of requiring default values. But if this would make the algorithm slightly faster, it is not a problem to come up with a default-constructed ID.