Questions about handling graphs in Mathematica, graph theory, graph visualization, GraphPlot, the built-in Graph type and the Combinatorica` package.

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3
votes
1answer
189 views

Merging Vertices of a Graph and adding up the edges weights

I have a Weighted Graph of g which looks like this. ...
0
votes
1answer
74 views

Testing Equality Expression?

Even if in Graph[{1 -> 2}] == Graph[{1 \[DirectedEdge] 2}] the answer is True ; but why MMA doesn't show the result of the ...
1
vote
3answers
157 views

Different Vertex Styling in a Graph

We can have this Graph: ...
2
votes
1answer
110 views

Distances of locations in the matrix form

I want to have the distances of the cities in the matrix form.How can I have it for example for the cities like followings that also includes the distance of the city from itself which is zero: ...
3
votes
0answers
226 views

How to compute the Lovász number for the given graph in Mathematica?

Here is a graph whose adjacency matrix is ...
0
votes
1answer
115 views

How can I replace UndirectedEdges to pairs of bi-directional DirectedEdge in a Graph?

How can I have pair of edges between nodes in this kind of graphs? ...
3
votes
1answer
196 views

Vertex Labeling Problem in a Graph

I am using following codes to create a graph. ...
14
votes
4answers
467 views

Can TreeForm be displayed “sideways”?

One recurrent problem I'm having with displays generated with TreeForm is that the expressions to be so displayed often at least one level with many (> 20) nodes ...
1
vote
1answer
92 views

Is there a TwoColoring function of Graph object?

The following code shows the GraphUtilities package makes a problem for Graph object. I want to use a ...
10
votes
1answer
559 views

Roads network visualization by thickness and color intensity by population from GIS files

We can have road networks of the countries in GIS shape file.For exmple from here. Normally traffic flows are proportionate to populations of the cities. I wonder how we can have the same in ...
5
votes
1answer
536 views

All possible topological orderings of a graph

TopologicalSort[] returns one of many unique orderings. From wikipedia: if a topological sort does not form a Hamiltonian path, the DAG will have two or ...
5
votes
1answer
75 views

Setting PropertyValue for VertexWeight is not persistent

g = CompleteGraph[8, VertexSize -> Medium]; PropertyValue[{g, VertexList[g][[1]]}, VertexWeight] = 10; PropertyValue[g, VertexWeight] ...
3
votes
1answer
52 views

Problems with PropertyValue when Graph's vertices are Lists

I create a Graph which vertices are lists (points in n-dimensional space) ...
2
votes
1answer
323 views

GraphPath: *all* shortest paths for 2 vertices, edge lengths negative

Mathematica uses Bellman-Ford to find a shortest path between two vertices when the edge lengths are negative: ...
3
votes
1answer
162 views

How can I highlight and individually color the connected components of a graph?

I have a graph G, and I wish to individually highlight and color the different connected components of a graph. It is simple enough to do this for one component: ...
1
vote
1answer
166 views

Do any users know of methods to capture Twitter feeds and subject them to analysis? [duplicate]

I would like to use the output of about 300 Twitter sources and would probably collect 30 minutes of tweets at a time and subject each collection to analysis; ideally this process would be automatic ...
1
vote
1answer
96 views

FindEdgeCut with weighted graphs

If I want to find a minimum cut between two nodes in a weighted graph, I would use FindEdgeCut as follows: ...
7
votes
1answer
271 views

Adding/deleting weighted edges to a weighted graph

How can I add and delete weighted edges in a weighted graph? Using Graph in Mathematica I want to add a weighted edge to a weighted graph. The problem is ...
1
vote
2answers
124 views

Separating disconnected graph objects without losing vertex coordinate assignments

Say I have a graph Gtest, which has multiple disconnected components. I found that I can isolate individual components while retaining vertex coordinate ...
9
votes
1answer
106 views

FindHamiltonianCycle is not invariant to edge permutation

Found this bug-like behaviour today: if the order of edges is changed so that VertexList does not return the vertices in canonical order, ...
0
votes
1answer
35 views

Parsing output from FindHamiltonianCycle to recover an ordered list of vertex positions for a discovered path

After applying FindHamiltonianCycle to a graph, one generates output that looks like the following: ...
3
votes
1answer
285 views

Generating a graph object where vertices are pixel coordinates and edges represent two pixels being in the same Moore neighborhood

I have a list of integer pixel positions, pts, and I wish to create one or more graph objects where vertices at these pixel positions share an edge if they are ...
2
votes
2answers
227 views

Manipulate graphs in 3D

Is it possible to Manipulate Graphs (e.g. a ...
3
votes
2answers
128 views

LineGraph Labels

I have a graph with labels on the edges: ...
5
votes
1answer
154 views

Keeping vertexcoordinates after adding a new vertex

I want to add a new vertex to a graph, with fixed VertexCoordinates but when I use VertexAdd, the new graph does not have the VertexCoordinates of the previous one. ...
5
votes
2answers
339 views

How to add new nodes to an existing graph with fixed (coordinates) nodes?

I'm ultimately trying to create a directed graph with some of the nodes in fixed positions and the other nodes placed around them in "acceptable" positions. It's better if I ask the question by ...
6
votes
2answers
342 views

Sierpinski carpet with GraphData

Is this graph in the list among the so-called "standard" structures used in GraphData? However, I have not found, yet, anything like "Carpet" or "Sponge" in the ...
1
vote
1answer
151 views

Find size of vertex image relative to the graph coordinate system

I am trying to define a graph using my own VertexShapeFunction with an ActionMenu button being the vertex and a custom ...
2
votes
2answers
388 views

EdgeRenderingFunction question

Bug introduced in 9.0 and fixed in 10.0.0 (Edit 1 : I added this paragraph after the original post, for context) Some context for this question can be found in another post ...
5
votes
3answers
238 views
2
votes
3answers
184 views

Graph with $\{a,b\}$ as Vertex Instead of Number

I'm trying to create a graph which has $\{a,b\}$ as labels: ...
9
votes
1answer
353 views

Drawing Zonotopes from Adjacency Matrix

This is crossposted in cs.stackexchange.com, but I have been trying to use Mathematica do this and figured it might be more appropriate to ask here. Define a "simple zonotope" to be a regular ...
4
votes
4answers
479 views

Graph Creation in Mathematica: TSP

I'm trying to create the following graph in Mathematica Where do I start? I'm specifically trying to make a graph so that I can use it in TravelingSalesman[g], ...
7
votes
1answer
195 views

How to scale edge length and keep layout of edge-weighted Graph?

I love using Graph as structure to store and visualize my data in Mathematica. Consider the following simple example for creating a ...
1
vote
0answers
122 views

Network problem of visualization of vertex

I have a question about visualization of network in Mathematica: for example: for this network g = ExampleData[{"NetworkGraph", "Friendship"}]; when we ...
6
votes
5answers
477 views

Building graph based on the cities connection?

I built a Graph based on the permutations of city's connections from : ...
5
votes
2answers
326 views

Colorize and the Four-Color Theorem

We can write: MorphologicalComponents[image] // Colorize To assign a random set of colors to each component in some image. The example used for reference by ...
6
votes
1answer
158 views

Graph rendering not working as expected

I'm running the older Mathematica v6 which seems to go through the edges of graphs twice. Is this a bug? Is it fixed on the latest version? Please just try this command: ...
1
vote
1answer
522 views

Adding an image background to a graph that uses vertexposition

Hello Mathematica stackexchange community! I need your help on a research project. I'm looking to create a graph g with vertices in specifies places and then use an image I have as the background of ...
2
votes
1answer
169 views

How to set FindGraphCommunities Modularity's method option

It is possible to set 2 options for one of FindGraphCommunities's methods "Modularity". They are "Weighted" and "StopTest". The question is how can one use the second option "StopTest"? What ...
2
votes
2answers
184 views

Adding Dynamic functionality to a Graph

I would like to make the edges and vertices of a Graph interactive, a simple demonstration is to change their colors: ...
4
votes
2answers
257 views

Efficiently determining the largest minimum cost to travel from a fixed source to an arbitrary sink in a weighted graph

Let $v_i$ be a vertex in a graph $G$ with vertices $(v_1,...,v_N) \in V$ and edges $(e_1,...,e_M) \in E$ with associated weights $(w_1,...,w_M)$. Let $v_s \in V$ be specified vertex in the graph. In ...
1
vote
0answers
181 views

Get path to end nodes in directed (partially cyclic) graph

I have a large directed graph containing small loops. I would like to extract all paths to all end nodes (no VertexOutComponent) with a given path length $n$. I ...
7
votes
3answers
372 views

I can't understand FindShortest Tour

I can't understand the function FindShortestTour because of the result: FindShortestTour[{ {0, 1}, {5, 1}, {2, 1}, {10, 1}}] ...
5
votes
2answers
2k views

How to find the Shortest Path, visiting ALL vertices, without coming back to the start (Hamiltonian Path, minimum distance)

A car has to pick up each person and take them to their destination. I am trying to find the shortest tour that will do this. How can I find the shortest path between any s and t.... visiting all ...
4
votes
0answers
117 views

Efficient Generation of Subgraphs (or, unfriend a friend a day)

NB: If you're not interested in the back-story, you could simply jump forward to the code which I'm seeking to optimize. Also, I believe this code would only work for MMA 8.0 and above. My friends ...
1
vote
1answer
455 views

Plotting a network or a graph with given coordinates for vertices

I'm new to Mathematica yet have coded a lot in MATLAB. Currently I'm working on a network simulation. My model is implemented in MATLAB, but I need to port it to Mathematica. Here is my question: ...
9
votes
3answers
382 views

FindShortestTour for charity (or: How can I optimize meal delivery with FindShortestTour?)

I've been wondering about this for a while - but never got around to asking - until I saw faleichik's incredible answer to Mathematica Minecraft. I did some work at a not-for-profit a little while ...
0
votes
1answer
146 views

Subset of edges with a different color

I want to color a subset of the edges of my graph with a different color. My graph currently has a large number of edges, so the following is just a toy example ...
0
votes
2answers
120 views

Basic question on producing non-overlapping graph nodes in a graph

I am plotting a graph which has about 196 nodes. ...