
Re: new Graph function + combinatorica: various problems
Posted:
Feb 12, 2011 5:19 AM


I posted on graph conversion a couple of weeks ago.
Shading of Graph can be prevented by prepending the System` context (System`Graph[...]).
The two versions of conversion yield different plots in GraphPlot. Also my conversion route both yield minimum and maximum spanning trees (although for the graphs I tested them, they look identical). The ToCombinatoricaGraph conversion yields graphs for which (for all graphs I tested) the minimum spanning tree does not plot.
Clearly, there is room for improvement in the graph area.
<< Combinatorica` << GraphUtilities`
myM8Graph = GraphData["ZamfirescuGraph48"]
(* conversion 1 *) myCombinatoricaGraph = FromAdjacencyMatrix[Normal[System`AdjacencyMatrix[myM8Graph]]];
myCombinatoricaGraph // ShowGraph MinimumSpanningTree[myCombinatoricaGraph] // ShowGraph MaximumSpanningTree[myCombinatoricaGraph] // ShowGraph
(* conversion 2*) myCombinatoricaGraph = ToCombinatoricaGraph[myM8Graph];
myCombinatoricaGraph // ShowGraph MinimumSpanningTree[myCombinatoricaGraph] // ShowGraph MaximumSpanningTree[myCombinatoricaGraph] // ShowGraph
Cheers  Sjoerd
On Feb 11, 10:20 am, Cupidio <andreatacche...@gmail.com> wrote: > Hi, > I'm experiencing some problems in combining the functionalities of > combinatorica and the builtin functions for graphs. > > In fact loading combinatorica shadows the builtin Graph function, and > makes its use impossible. But while I need some of the functions in > the combinatorica package (minimum/maximum spanning tree), i prefer > the graphic and "lexical" representation of the builtin Graph[]. > > How do I "save" Graph[] when I load combinatorica, or how can I make > it come back? > > Also (and this looks weird!), when i use ToCombinatoricaGraph[] (in > GraphUtilites package) to convert a graph, the resulting object can be > processed by MaximumSpanningTree[], yielding a correct result, but not > by MinimumSpanningTree[] which returns something like: > > MinimumSpanningTree[Graph:<14,8,Directed>] > > ...not even a combinatorica graph object. > > Thanks for your help!

