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

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0answers
56 views

Purpose of VertexWeight

I am trying to partition a graph into partitions of equal weight (on the vertex). I looked at the documentation, and found VertexWeight, which seems to attach a weight to a vertex. In the details, ...
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3answers
460 views

Label multiple edges between same vertices

I have a simple graph with multiple edges between two vertices, say: Graph[{ Labeled[a -> b, "A"], Labeled[a -> b, "B"] }] Unfortunately, Mathematica ...
3
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1answer
90 views

Change group generators?

I want to make Cayley graphs for the same group, but with different generators. Is there any way to represent a group, besides a cumbersome permutation representation or using the default Mathematica ...
2
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1answer
530 views

How to implement the directed Barabasi-Albert algorithm in Mathematica?

Does anyone know how to implement an efficient version of the [directed Barabasi-Albert algorithm][1] in Mathematica that scales until hundred of thousands nodes? The directed network mechanism is ...
3
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1answer
90 views
17
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4answers
945 views

How to find all vertices reachable from a start vertex following directed edges?

How to find all vertices reachable from a given start vertex following directed edges, in a cyclic directed graph given as ...
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1answer
83 views

How to insert Tooltip into incidence plot?

I'm trying to make a graph using a file .NET extracted from a file .CSV and to make tooltiped the vertices' labels. Initially I ...
3
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1answer
65 views

AdjacencyList of DirectedEdges in Graph ignore edge direction

I have a simple tree graph with directed edges: In: AdjacencyList[Graph[{a -> b, a -> c, b -> d, b -> e}], b] Out: {a, d, e} I wonder how I can ...
3
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1answer
78 views

Specifying the style of edges in directed graphs [closed]

How do I specify the style of individual edges in a directed graph (in Mathematica version 9)? Consider maybe this ...
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0answers
75 views

Is it possible to use EdgeCapacity in FindMinimumCostFlow?

I'm having trouble getting the EdgeCapacity feature in FindMinimumCostFlow to work. I have attached a simple example. We have a simple graph of four vertices. There are two paths from the "source" ...
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1answer
69 views

FindCycle not working as expected for multigraph

Say I have a simple multigraph like so: edges = {DirectedEdge[a, b], DirectedEdge[b, c], DirectedEdge[c, a]}; g = Graph[Join[edges, edges]] ...
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0answers
46 views

Export format for graphs loses type information?

I have a situation where I am adding properties to vertices in my graph. In my case, I am adding a moduleId, which is an integer, and a kind, which is a string. I attach a weight to the edge as well. ...
2
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0answers
57 views

Bugs in VertexContract function?

I think there may be two bugs in the VertexContract function: 1) The updated graph does not include reasonable edgeweights 2) The function does not actually reduce the number of vertices in the ...
2
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1answer
178 views

Dynamic process on graph

I have a question, which I failed to find an answer to myself. I'm a casual user of Mathematica, but do have some knowledge about Dynamic module and other "Advanced" features. My problem is ...
2
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1answer
72 views

Finding if a graph contains an even cycle

I am looking for a simple boolean-like function which could check if a graph contains an even cycle. I'm aware there is ExtractCycles but I'm looking for a true/false output than a list of cycles.
4
votes
1answer
201 views

Intelligent vertex placement in large tree graphs

This question about graph layout is fairly general, but can be illustrated in the case of the Collatz Conjecture. Collatz created the following function over integers greater than 1: If the integer ...
3
votes
1answer
103 views

How to change the vertex shape

(Using V9 on Ubuntu) Consider the following code, to create a graph. ...
2
votes
1answer
152 views

(Tree) Graph Layout

I am trying to draw a graph in a tree-like form. I can't use TreeGraph because what I am drawing is not properly a tree (has loops) so TreeGraph won't draw it. Here is the code: ...
2
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1answer
93 views

Overlapping EdgeLabels

I have to make a directed graph for a maximum flow algorithm assignment. Although I have managed to make the graph for the better part, it still needs some work. The problem is that Mathematica ...
3
votes
2answers
137 views

Slow rendering in GraphPlot3D

Is there a way to speed up this rendering? I have to make this call many times in order to make an animation of some dynamics on the graph g. Thus dynamics are carried in the list var. Each entry in ...
1
vote
1answer
111 views

Coloring vertices according to a function using GraphPlot3D

This question is similar but not identical to a related question called: coloring-vertices-using-graphplot . I need to color the vertices of a graph according to a function, f that is defined on the ...
2
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4answers
167 views

Invisible graph edges

I have a fairly sparse adjacency matrix for which I can draw the graph. Right now, two nodes $i$ and $j$ are connected, or not ($w_{ij} \in \{0,1\}$). However, I have come up with a way to define new ...
1
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1answer
54 views

Having trouble using different options with GraphPlot [closed]

I am extremely new to Mathematica and I am trying to plot some graphs. GraphPlot[{1->2, 2->3, 3->1}] works just fine. But as soon as I try to use ...
3
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1answer
183 views

Interpreting a formula from Graph Theory - where do x and y come from?

I'm trying to understand the generating function for OEIS A062734, which is in Mathematica. Essentially, despite knowing no Mathematica at all, I think I can parse most of it, but where do $x$ and $y$ ...
2
votes
1answer
45 views

VertexConnectivity and FindVertexCut disagree [duplicate]

I'm trying to use Mathematica to compute the minimal vertex cut for graphs. From what I understood, VertexConnectivity of a graph should correspond to the number of vertices in the minimal vertex cut. ...
6
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2answers
268 views

Is there something wrong with VertexConnectivity

Note: this is fixed in version 10. As I noticed in the documentation VertexConnectivity is defined as the following The vertex connectivity of a graph $g$ is ...
2
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1answer
266 views

Vertex Names as Labels in GraphPlots

I'm trying to use GraphPlot to draw a Graph which is constructed from an adjacency matrix and am having trouble with the labels in the plot. I am doing (data is a silly example) the following: ...
1
vote
2answers
113 views

Split graph into independent maximal cliques?

Does Mathematica have a method to partition the vertices of a graph into maximal independent subsets, such that each subset generates a complete subgraph? Edit: The partition should be maximal in the ...
3
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0answers
86 views

FindGraphCommunities method options?

FindGraphCommunitites has a couple of method options: "Modularity", "Hierarchical", ...
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3answers
104 views

How to control which nodes get placed at each radius with GraphLayout → “RadialEmbedding”?

I have a directed graph each of whose nodes belongs to exactly one of three groups: "sources", "sinks", and "both". As these names suggest, nodes in the "sources" group have only outgoing edges; ...
2
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0answers
94 views

Is there a minor bug in Neal Alexander's TopologicalSortAll[]?

There is an amazing answer to this question: All possible topological orderings of a graph By Neal Alexander. However, as user "dark blue" (I am not this user) notes: ...
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1answer
85 views

Twisting a graph layout (by fixing the $x$ coordinate of all its vertices)

I would like to draw a given graph $G$ in a specific way and I would like to know whether Mathematica can do it in a (semi-)automated way. My goal is to draw the graph $G$ in 2D, fixing all the $x$ ...
0
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1answer
81 views

How to use Hold on a variable defined as a graph

I'm working on doing operations on different graphs and getting their probability node degree distributions using a simple algorithm. If I have many defined graphs, for example: ...
6
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2answers
157 views

Test existence of a path from one side of a graph to another

I'm trying to determine how I can test if a path exists from one side of a graph to another as efficiently as possible. If I have the Lines given by: ...
4
votes
1answer
123 views

Minimal Colouring of Graph Vertices

Is there a way to colour graph vertices minimally in new Mathematica? I tried loading MinimalVertexColoring with the old Combinatorica package but it doesn't work ...
4
votes
1answer
129 views

FindShortestPath with VertexWeight

I have a weighted graph on which I want to perform some FindShortestPath calculations. However, the problem is that my weights are defined for vertices with ...
7
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0answers
47 views

What system functions use VertexWeights?

EdgeWeights -> are used by a lot of functions, but I can't find any exposed usage for VertexWeights ->. I'm not asking ...
27
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4answers
4k views

How to generate a random tree?

Is it possible to generate a random tree without explicitly constructing a random adjacency matrix that satisfies tree properties? How about a random directed tree? Edit: incredible answer by ...
4
votes
1answer
346 views

Map of all graphs obtainable with GraphData?

I've been trying to put together an answer to another question, but I am stuck, so I decided to post this question instead. Mathematica contains (among its curated data) information on definition, ...
1
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1answer
169 views

Can degenerating Nicomachus' triangle down to $0$ area by using `Graph` be done?

I noticed a pattern in Nicomachus' Triangle that might be used to reduce the triangle to the number line. If the Edge size could be set to the absolute difference ...
6
votes
2answers
151 views

Visualizing subgraphs while specifying the locations of vertexes

I would like to visualize separate connected components of a graph defined by data points lying in the two-dimensional plane by surrounding each connected component subgraph by a bounding curve. I ...
4
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1answer
78 views

Edge Labels with distance between vertices

I am trying to make traveling salesman type graph using the locations of NFL stadiums as the vertices. I need to get the EdgeLabels to appear was the distance between the vertices. I was able to ...
4
votes
1answer
129 views

System of differential equations on a directed graph

I want to use Mathematica to model blood flow through a capillary network. The approach we are using is going to be to create a directed graph, and have a system of differential equations at each ...
1
vote
2answers
121 views

How do you apply an algorithm individually to an array with many graphs

I have and array with many graphs to which I want to apply an algorithm (below) to each graph in an array that contains all my graphs. ...
2
votes
1answer
161 views

Community detection on weighted graphs?

The documentation says that FindGraphCommunities works with weighted graphs. I've been playing around with a complete graph with weighted edges, and FindGraphCommunities always returns a single ...
2
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0answers
68 views
0
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0answers
58 views

Transform NMinimze into LinearProgramming formulation

I have the following maximization problem that I currently try to solve with Minimize/NMinimize. Unfortunately, this kind of solution method takes really long for large systems of equations and ...
3
votes
1answer
161 views

Visually Separating Cliques in Graphs

I have a graph with 189 vertices, more than 10,000 edges and 20 cliques. As one can imagine, this graph is a mess when trying to display it. I'd really like to display the graph, separated into ...
52
votes
2answers
10k views

How can I use Mathematica's graph functions to cheat at Boggle?

Boggle is a word game played with 16 dice and a 4x4 tray. This question is inspired by a Stack Overflow question about Boggle that I decided to solve using Mathematica. In addition to Mathematica, I ...
1
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1answer
194 views

Changing the size of arrows in a directed graph?

How can I change the size of arrows in a directed graph? By default, the arrows are too big and clutter the graph.