Can someone provide an example of a Combinatorica-based graph which uses ShowGraph and Graph and takes in an explicitly defined list of edges (not some auto-generated graph). I have not been able to find any documentation which describes the expected input format.
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1 Answer
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Two examples:
Needs["Combinatorica`"]
GraphicsRow[
{ShowGraph[
g1 = Graph[{{{1, 2}}, {{2, 3}}, {{3, 1}}}, {{{1, 1}}, {{2, 1}}, {{3, 3}}}],
VertexNumber -> True],
ShowGraph[
g2 = Graph[
{{{1, 2}, EdgeLabel -> "lbl1"}, {{2, 3}, EdgeColor -> Green},
{{3, 1}, EdgeLabel -> "(3,1)", EdgeDirection -> True, EdgeLabel -> True,
EdgeLabelPosition -> UpperLeft}},
{{{1, 1}, VertexLabel -> True, VertexLabelColor -> Blue,
VertexLabelPosition -> LowerRight},
{{2, 1}, VertexNumber -> True, VertexNumberColor -> Orange},
{{3, 3}}}]
]}]
to get
EDIT: Before loading Combinatorica you can transform the data using:
toCombGrphData[gr_] := gr //
Sequence @@ {EdgeList[#] /. UndirectedEdge[x__] :> {List[x]},
List /@ (AbsoluteOptions[#, VertexCoordinates][[2]])} &
Update: For Version 9, we need to change the part specification above from [[2]] to [[1,2]] (thanks: @sam84).
Example:
combgrpg = toCombGrphData[CompleteGraph[3]]
gives the edge list and vertex coordinates needed as input for Combinatorica ``Graph`:
(* Sequence[{{{1, 2}}, {{1, 3}}, {{2, 3}}}, {{{0.866025, -0.5}}, {{-0.866025, -0.5}}, {{-2.44929*10^-16, 1.}}}] *)
Then,
Needs["Combinatorica`"]
ShowGraph[Graph[combgrph]]
gives
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$\begingroup$ I tried your example in Mathematica 9, but I obtain the following error: Part::partw: Part 2 of {VertexCoordinates->{{-0.866025,-0.5},{0.866025,-0.5},{1.83697*10^-16,1.}}} does not exist. >> $\endgroup$sam84– sam842014-04-18 17:19:21 +00:00Commented Apr 18, 2014 at 17:19
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$\begingroup$ I fixed it. This function works: toCombGrphData[gr_] := gr // Sequence @@ {EdgeList[#] /. UndirectedEdge[x__] :> {List[x]}, List /@ (AbsoluteOptions[#, VertexCoordinates][[1, 2]])} & $\endgroup$sam84– sam842014-04-19 09:32:49 +00:00Commented Apr 19, 2014 at 9:32
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$\begingroup$ It is possible to extend the function toCombGrphData so to inclue also edge weights? Thanks $\endgroup$sam84– sam842014-04-19 09:33:44 +00:00Commented Apr 19, 2014 at 9:33
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$\begingroup$ @sam84, can't recall the
Combinatoricasyntax for using edge weights. If you have simple example handy, perhaps you can post a new question. (Thanks for the fix; I will update the post with the fix.) $\endgroup$kglr– kglr2014-04-19 14:46:04 +00:00Commented Apr 19, 2014 at 14:46
Combinatorica`GraphunderMore Informationon the pageCombinatorica/ref/Graphin the documentation center $\endgroup$