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Re: Re: Re: Re: changing


Murray Eisenberg wrote:

>But how do I get GraphPlot to use labels that _I_ specify, rather than 
>numbers -- when using a graph created with Combinatorica and without 
>having to directly specify the labels as part of the graph structure.
>
>For example:
>
>   g=Cycle[6];
>
>   GraphPlot[g,
>     VertexLabeling->True,VertexRenderingFunction->(Text[...]&)]
>
>This sort of thing doesn't produce any vertex labels even if I first use 
>something like:
>
>   g = SetGraphOptions[g, VertexLabel -> Characters["b,a,f,e,d,c"]];
>  
>
The VertexLabel option can take Boolean values only. Perhaps you meant:

g = SetVertexLabels[Cycle[6], {b,a,f,e,d,c}];

GraphPlot[g, VertexLabeling -> True]

Carl Woll
Wolfram Research

>(Comment:  The documentation about graph display is really atrociously 
>inadequate!)
>
>Carl Woll wrote:
>  
>
>>Murray Eisenberg wrote:
>>
>>    
>>
>>>Yes, GraphPlot seems to permit making nice vertices (or edges), but then 
>>>the labeling -- either with a Graph object from Combinatorica or just 
>>>the kind of graph described by the GraphPlot reference page -- does not 
>>>seem to admit vertex labels or edge labels, at least so far as I can 
>>>see.  For example, neither of the following displays either vertex 
>>>labels or edge labels:
>>>
>>>
>>>GraphPlot[Cycle[3], Method -> Automatic, VertexLabeling -> True,
>>> EdgeLabeling -> True, EdgeRenderingFunction -> ({Black, Line[#1]} &),
>>>  VertexRenderingFunction -> ({EdgeForm[{Thickness[0.005], Red}],
>>>     Yellow, Disk[#1, 0.04]} &)]
>>>
>>>GraphPlot[{{v1 -> v2, "a"}, {v2 -> v3, "b"}, {v3 -> v1, "c"}},
>>> Method -> Automatic, VertexLabeling -> True, EdgeLabeling -> True,
>>> EdgeRenderingFunction -> ({Black, Line[#1]} &),
>>> VertexRenderingFunction -> ({EdgeForm[{Thickness[0.005], Red}],
>>>     Yellow, Disk[#1, 0.04]} &)]
>>>
>>>On the other hand, if I remove he VertexRenderingFunction option, I do 
>>>see vertex labels on the default (yellow boxes) vertex shapes:
>>> 
>>>
>>>      
>>>
>> From the help for VertexLabeling:
>>
>>"Any explicit setting for VertexRenderingFunction overrides the setting 
>>for VertexLabeling."
>>
>>Similarly for EdgeLabeling.
>>
>>If you want labels when using VertexRenderingFunction, you need to put 
>>them in explicitly in the VertexRenderingFunction rhs. The first example 
>>in the VertexRenderingFunction function page does this.
>>
>>If you want to recreate the default labeling inside 
>>VertexRenderingFunction, the following may help:
>>
>>VertexRenderingFunction -> (Text[
>>      Framed[#2, {Background -> RGBColor[1, 1, .8], FrameStyle -> 
>>RGBColor[.94, .85, .36], FrameMargins -> Automatic}], #] &)]
>>
>>Carl Woll
>>Wolfram Research
>>
>>    
>>
>>> GraphPlot[{v1 -> v2, "a"}, {v2 -> v3, "b"}, {v3 -> v1, "c"}},
>>>  Method -> Automatic, VertexLabeling -> True,
>>>   EdgeLabeling -> True, EdgeRenderingFunction -> ({Black, Line[#1]} &)]
>>>
>>>GraphPlot[Cycle[3], Method -> Automatic, VertexLabeling -> True,
>>> EdgeLabeling -> True, EdgeRenderingFunction -> ({Black, Line[#1]} &)]
>>>
>>>Of course this now defeats the purpose of using GraphPlot so as to get 
>>>exactly the kind of vertex shapes that VertexRenderingFunction, above, 
>>>provides.
>>>
>>>Similarly with EdgeRenderingFunction.
>>>
>>>The kernel function GraphPlot doesn't seem to mesh very well with 
>>>Combinatorica's graph functions.  This all still seems only "half-baked".
>>>
>>>
>>>J. McKenzie Alexander wrote:
>>> 
>>>
>>>      
>>>
>>>>Take a look at GraphPlot, the graph rendering function that is built 
>>>>into the Mathematica kernel.  I switched from using ShowGraph to 
>>>>GraphPlot after realising that it was (a) faster and (b) easier to 
>>>>customise.  Here's what you want:
>>>>
>>>>GraphPlot[
>>>>Cycle[3],
>>>>Method -> None,
>>>>EdgeRenderingFunction -> ({Black, Line[#1]} &),
>>>>VertexRenderingFunction -> ({EdgeForm[{Thickness[0.005], Red}], Yellow,
>>>>    Disk[#1, 0.04]} &)
>>>>]
>>>>
>>>>You need to specify Method->None, otherwise GraphPlot will override the 
>>>>specified positions of the vertices in the graph and use its own default 
>>>>vertex positioning algorithm.
>>>>
>>>>VertexRenderingFunction is what you need to define in order to customise 
>>>>the appearance of the vertices.
>>>>
>>>>I provided a definition of EdgeRenderingFunction just so that the edges 
>>>>are rendered in the same way as ShowGraph.
>>>>
>>>>Cheers,
>>>>
>>>>Jason
>>>>
>>>>-- 
>>>>J. McKenzie Alexander
>>>>Department of Philosophy, Logic and Scientific Method
>>>>London School of Economics and Political Science
>>>>Houghton Street, London WC2A 2AE
>>>>
>>>>
>>>>On 7 Mar 2008, at 07:29, Murray Eisenberg wrote:
>>>>
>>>>   
>>>>
>>>>        
>>>>
>>>>>With Mathematica 6, I can change the default style (medium black disk)
>>>>>for rendering the vertices of a Combinatorica Graph like this:
>>>>>
>>>>> Needs["Combinatorica`"]
>>>>>
>>>>> g = Cycle[3];
>>>>> ShowGraph[g, VertexStyle -> Disk[Large], VertexColor -> Red]
>>>>>
>>>>>But how can I, for example, change the vertex style so it is, say, a
>>>>>large yellow disk with a thick red boundary?  Or even just change it to
>>>>>be a circle?  I tried "obvious" things like the following, but they
>>>>>cause errors:
>>>>>
>>>>> ShowGraph[g, VertexStyle -> Graphics[Circle[], ImageSize -> 20]]
>>>>>
>>>>>-- 
>>>>>Murray Eisenberg                     murray at math.umass.edu
>>>>>Mathematics & Statistics Dept.
>>>>>Lederle Graduate Research Tower      phone 413 549-1020 (H)
>>>>>University of Massachusetts                413 545-2859 (W)
>>>>>710 North Pleasant Street            fax   413 545-1801
>>>>>Amherst, MA 01003-9305
>>>>>
>>>>>     
>>>>>
>>>>>          
>>>>>
>>>>
>>>>Please access the attached hyperlink for an important electronic 
>>>>communications disclaimer: 
>>>>http://www.lse.ac.uk/collections/secretariat/legal/disclaimer.htm
>>>>
>>>>   
>>>>
>>>>        
>>>>
>>> 
>>>
>>>      
>>>
>>    
>>
>
>  
>



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