Define heterogeneous renumbering API

[seunghwak]

Defines a heterogeneous renumbering function that renumbers sampled edge list vertex & edge IDs to consecutive integers per vertex & edge type, respectively.

The renumbered edges are sorted. New functions that sort & compress will be added later.

[seunghwak]

@alexbarghi-nv In heterogeneous renumbering, can I assume that vertex types are always used? Or there can be a use case with no vertex type but just edge types?

Similarly, is there a use case with vertex types but no edge types & IDs? (i.e. should the input edgelist_edge_ids and edgelist_edge_types be std::optional?)

[alexbarghi-nv]

@alexbarghi-nv In heterogeneous renumbering, can I assume that vertex types are always used? Or there can be a use case with no vertex type but just edge types?

Similarly, is there a use case with vertex types but no edge types & IDs? (i.e. should the input edgelist_edge_ids and edgelist_edge_types be std::optional?)

@alexbarghi-nv In heterogeneous renumbering, can I assume that vertex types are always used? Or there can be a use case with no vertex type but just edge types?

Similarly, is there a use case with vertex types but no edge types & IDs? (i.e. should the input edgelist_edge_ids and edgelist_edge_types be std::optional?)

It is safe to assume that if there are edge types, then there are also vertex types, and vice versa.

[alexbarghi-nv]

This looks good to me. I had a long question typed out about compression, but then my tab crashed and I lost it. Anyways, we can worry about compression later. This API looks good.

[alexbarghi-nv]

👍

[alexbarghi-nv]

Because the performance gain of CSR format is pretty small for PyG, I think implementing this function is sufficient for our 24.08 goals for heterogeneous renumbering.

[ChuckHastings]

/merge