Getting the automorphism group from NAUTY

[rightleftspin]

For a project I am working on, I am hoping to get the elements of the automorphism group for a graph I see that the library already returns the size of the automorphism group. How much work would it be to also return the elements of the automorphism group? If you could point me towards how to do that, I would be more than happy to add this feature.

Also, I'm sorry to be submitting this issue when I haven't finished working on the other issue, a lot of stuff has come up, but I am back to working on it now.

[mxhbl]

Hi, thanks for opening the issue. You are right, returning the elements of the automorphism group should really be implemented. I will hopefully have time to work on this soon.

In the meantime, you can get information on the automorphism group simply from the output of densenauty https://github.com/mxhbl/NautyGraphs.jl/blob/2163daf957c05ab27fcbf933f480341fb71e9653/src/nauty.jl#L86.
For example, the orbits of the automorphism group are stored in the orbits array. See the nauty user guide for a more complete description.

[rightleftspin]

I sent in a pull request, this is the first pull request I've contributed to a repository, so any criticism is incredibly helpful!

As a separate math question, do you have any idea, off the top of your head, if its possible to efficiently construct the automorphism group of a graph from its orbits?

[mxhbl]

#15 now makes it possible to read out graph orbits. Logging group generators is a bit more tricky, as nauty only lets you write those to a file (or a global variable).
One way to get around that would be to redirect nauty's output to stdout, which we can then itself redirected to a buffer. I will try to implement that in the near future.

[rightleftspin]

This works perfectly, thank you so much! I think its possible to get the automorphism group from the graph orbits so I think I'll go with that for now, but if you get a chance to implement that, it would be incredibly helpful!

[mxhbl]

Great! I will keep this open until generators are implemented