# incompleteness tolerance for the CSR input

Hello,

[Question] Has the CSR encoding to be complete, in the sense that each edge has to be mentioned in the adjacency lists of both the vertices it is incident to?

[Background]

I use Mesh2Dual to generate a CSR coded graph from a 3-dimensional mesh. This represent a three-dimensional domain where fluid dynamics are to be simulated.

Before I promote this graph to PartKway, I have to merge this graph with several binary trees, which are thought to be embedded into the 3-dimensional domain. I want to put edges between the embedded trees and certain vertices of the domain graph (actually I want to connect a tree vertex to the part of the domain it belongs to)

It is rather straight-forward how generate the csr encoding for the merged graph from the two original graphs (provided you know how you want it to be). However this is rather cumbersome to write and debug, even more if this ought to be fast.

It would be easier, if I could simply write these edges into the csr encoding of the trees, rather than changing the autogenerated graph for the mesh, too.

Thank you very much

Nihility

## RE: Yes. For each edge (u,v) the

Yes. For each edge (u,v) the CSR structure of the graph should contain an entry for v (i.e., (u,v)) and an entry for u (i.e., (v,u)).