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Graph and network GUI creation with Yed & Wolfram: importing diagrams

Posted 16 days ago
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I Have been working in some graph theory practical applications like PERT and Simple Line Assembly Balance Problem (Mainly Industrial Engineering topics) and I reached a workflow pretty replicable and comfortable that reduced my graph creation/edit time more than 30%.

Recommended case of use: When the graph you need to create have more than 6 nodes and more than 10 connections.

The tools we need are just a piece of open source software called Yed, it is free and well designed, basically it is a graph editor and diagram tool that will allow us to create our graphs to the import them into Mathematica.

  1. Open Yed And create a graph. To change the node label press ENTER and write the name, to change the edge weight do the same with the connection of two nodes. For instance, try the following graph:

Example Yed graph

  1. Go to File menu > Save as... and select GML
  2. You can use the import function, however I realized that the weights are not preserved and are turned into edge labels, also the vertex names are not the ones we write in the Yed editor. So I wrote this piece of code to change the properties and match them to the graph editor:

    TransformGML[file_] := Module[
      {g1, rules, vertex, edges, sus},
      g1 = Check[Import[file], Missing];
      vertex = VertexList[g1];
      edges = AnnotationValue[{g1, #}, EdgeLabels] & /@ EdgeRules[g1];
      rules = EdgeRules[g1];
      sus = AnnotationValue[g1, VertexLabels];
      Graph[Replace[#, sus, {1}] & /@ rules, EdgeWeight -> edges, 
       VertexLabels -> Thread[(sus[[All, 1]] /. sus) -> sus[[All, 2]]]]
  3. Run calculations into the new graph to verify that it matches the graphical editor:

    WeightedAdjacencyMatrix[g1] // MatrixForm
    0   15    20 0   0
    0   0 0   0 30
    0   0 0   5 0
    0   0 0   0 8
    0   0 0   0 0 
    Graph[g1, GraphStyle -> "IndexLabeled", EdgeLabels -> "EdgeWeight"]

Resulting into the (equivalent) graph:

Equivalent graph

I hope this may be helpful to someone, also if you have a better way to import external graph created files let me know!

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