Re: Relationship between vertices and indices with GraphDistanceMatrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg111605] Re: Relationship between vertices and indices with GraphDistanceMatrix*From*: "Jon Harrop" <usenet at ffconsultancy.com>*Date*: Sat, 7 Aug 2010 01:31:36 -0400 (EDT)*References*: <i3bd2v$pe0$1@smc.vnet.net>

"Daniel Lichtblau" <danl at wolfram.com> wrote in message news:i3bd2v$pe0$1 at smc.vnet.net... > Jon Harrop wrote: >> Given a graph represented as edges between vertices, such as the >> following: >> >> g = {"1" -> "2", "1" -> "10", "1" -> "11", "2" -> "3", "2" -> "18", >> "3" -> "4", "3" -> "12", "4" -> "5", "4" -> "19", "5" -> "6", >> "5" -> "13", "6" -> "7", "6" -> "20", "7" -> "8", "7" -> "14", >> "8" -> "9", "8" -> "16", "9" -> "10", "9" -> "15", "10" -> "17", >> "11" -> "15", "11" -> "12", "12" -> "13", "13" -> "14", >> "14" -> "15", "16" -> "20", "16" -> "17", "17" -> "18", >> "18" -> "19", "19" -> "20"} >> >> You can use GraphDistanceMatrix to compute the all-pairs shortest paths >> as a >> matrix. However, without knowledge of the mapping from vertex names to >> indices in the resulting matrix, the output is useless. So how are you >> supposed to use this function? > > Needs["GraphUtilities`"] > > VertexList will retain the correspondence between your vertex names and > the vertex positions in the adjacency matrix. > > In[145]:= ag = AdjacencyMatrix[g]; > InputForm[vl = VertexList[g]] > > Out[146]//InputForm= > {"1", "2", "10", "11", "3", "18", "4", "12", "5", "19", "6", > "13", "7", "20", "8", "14", "9", "16", "15", "17"} Ah, thank you! Cheers, Jon.