Create VisualizationCore.jl and VisualizationBase.jl, allow visualizing NamedGraph and DataGraph without loading ITensorNetworks

[emstoudenmire]

The following code is leading to an error:

using NamedGraphs.NamedGraphGenerators: named_comb_tree
using ITensorGLMakie

let
  g = named_comb_tree([3,3,3])
  @visualize g
end

This is with the following package versions:
GraphMakie v0.5.6
GeometryBasics v0.4.11
UnicodePlots v3.6.4
ITensorNetworks v0.11.14
Graphs v1.11.1
GeometryBasics v0.4.11

[mtfishman]

I see what's going on. In order to visualize NamedGraph you need to load ITensorNetworks.jl as well.

There is a generic definition of visualize for AbstractGraph: https://github.com/ITensor/ITensorVisualizationBase.jl/blob/v0.1.11/src/visualize.jl#L106-L109 but it assumes the vertices are integers, so when it gets non-integer vertices it throws the error you are seeing deep down in the code.

This definition in ITensorNetworks.jl: https://github.com/ITensor/ITensorNetworks.jl/blob/v0.11.14/src/visualize.jl#L5-L19 adds support for non-integer vertices.

Ideally we would have a VisualizationCore.jl or VisualizationInterface.jl package that is independent of ITensors.jl that defines the visualize/@visualize interface, and then we could add package extensions NamedGraphsVisualizationCore.jl, DataGraphsVisualizationCore.jl, ITensorsVisualizationCore.jl, ITensorMPSVisualizationCore.jl, ITensorNetworkVisualizationCore.jl, etc. Unfortunately for the time being without that the definitions for visualizing certain types are spread out a bit randomly.

[emstoudenmire]

Yes, I can confirm that adding using ITensorNetworks does fix the problem. I see, so there are sort of layers of features that are split across some packages. Not a problem for now, since this isn't so high-priority, but good to know what the issue is here and what a solution could be.