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.
- 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:
test.bmp (354 KB)
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Go to File menu > Save as… and select GML
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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]]]] ] -
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:
I hope this may be helpful to someone, also if you have a better way to import external graph created files let me know!