# Tagged Questions

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

2k views

### Drawing pairs (planar graph, circle packing)

Circle packing theorem states: For every connected simple planar graph G there is a circle packing in the plane whose intersection graph is (isomorphic to) G. How to use Mathematica to draw examples ...
139 views

### FindHamiltonianCycle is not invariant to edge permutation

Bug introduced in 9.0.1 or earlier and fixed in 10.0 Found this bug-like behaviour today: if the order of edges is changed so that VertexList does not return the ...
45 views

### How to perform operations with vertices from any edge on a Graph object

I'm trying to get the vertices from an large list of edges on a Graph object in Mathematica 10. I need to operate them, adding, substracting dividing. As an ...
59 views

### Why does (Layered)GraphPlot lose labels and renumber vertices?

I define a graph of numbers as vertices, but also labeled, like g=Graph[{Labeled[1 \[DirectedEdge] 5, "text1"]…},VertexLabels -> {79 -> "text2",…}]. This is ...
70 views

### Count graphs with fixed number of vertices incluing isomorphisms [closed]

I'm trying to use the listgraph function in the Combinatorica package: Needs["Combinatorica"] g = ListGraphs[5]; ShowGraph /@ g However, it only returns all the ...
191 views

### Arbitrary shape GridGraph

There is a function GridGraph that generates a finite square lattice graph. Is there a way to make a generalized solution (e.g. with hexagons, or triangles instead of squares)? To put it in more ...
75 views

### Network Graph: show highly connected components

I want to create a network graph without the small subgraphs which are disconnected from the big network graph. Suppose I want to visualize the edgelist: ...
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### Graph, overlapping vertexlabels

The graph I create is based on more then 1000 different word-combinations. A example looks like this: text = {{word, word1}, {word1, word2}, {word1, word3}, {word,word4}, {word,word5}, {word,...
47 views

### Can I rely on the ordering of the adjacency matrix? [closed]

Suppose I have created a Graph[{1,2..n}, {1->3, etc}], and I take the adjacency matrix of that graph. Can I rely on the fact that the i-th entry in the graph is the i-th node in the matrix? Or maybe ...
94 views

### Multi-named Vertices (or Overlapping Vertices) in TreePlot/LayeredGraphPlot, or Merging Trees

If there is a series of rules from which a TreePlot/LayeredGraphPlot is made: ...
205 views

### How to rotate a complete graph without image rescaling while rotating

How do I rotate the following image? ...
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### How can I get the vertex labels of an existing graph?

For example, if there is a graph g = CompleteGraph[5, VertexLabels -> {1 -> "v1", 2 -> "v2", 3 -> "v3", 4 -> "v4", 5 -> "v5"}] How can I later ...
91 views

### Compute complete graph and make minimum spanning tree

I'd like to plot a complete Graph and then compute the Minimum spanning tree of it. I already can make a complete graph out of a list that countrydata gives me: ...
111 views

### Iterative Tree Plot for the Sum of an Integer's Digits Squared

I am trying to make a graph that depicts integers<100 mapping to the sum of their digits squared. I can do this for one iteration, but I don't know how to do it for more than one, or until the new ...
122 views

### What is the correct way to assign and use properties of vertices in graphs?

I'm using Mathematica 10, but I'm having a hard time getting it to do anything useful for network analysis because I'm having a hard time working with node properties and analyzing the graph by its ...
66 views

### Graph: vary color/length vertextlabels based on frequency

In this example I use a small network of 5 words. ...
99 views

### Slow-down encountered for RandomChoice in large lists

I was wondering if anyone could help me to speed up this code snippet which creates simple (sparse) networks by preferential attachment. The algorithm adds a vertex and an edge each time interval. ...
159 views

### Computing Domination Numbers of Graphs

Is there a way to get Mathematica to compute the domination number (size of the smallest dominating set) of a graph? There doesn't seem to be a direct command for this, so I'm not sure if there would ...
49 views

### reset the value of a variable [closed]

Folks, I have a problem in populating a matrix without overriding the values. After performing computations for various values for j, I want to store these values in following matrix. Here is the code:...
78 views

### Shortest Common Superstring for all k-length strings on an alphabet

Given all strings of length $k$ of an alphabet of size $n$. This gives $n^{k}$ strings. Now I want to create one superstring that contains all these strings as substrings. They hopefully strongly ...
412 views

### Efficiently find all connected subgraphs

Is there a way to generate all the connected subgraphs of a graph in mathematica without going through all the subsets of the nodes and checking if the subgraph is connected (which will be O(2^N)*O(...
470 views

### Display a labeled multigraph

Introduced in version 9, fixed in version 10. Thanks Szabolcs for providing this screenshot showing that the bug is fixed. Despite the integration of graphs and networks, multigraphs are ...
297 views

### Distinguishing left from right adjacent triangles in triangle mesh [closed]

What I'm trying to do: I'm trying to create a path-drawing function which will produce a path like the one I-P in the diagram below. The way this path was generated requires me to swap between the ...
86 views

### Why does TreePlot ignore the vertex labels in a TreeGraph argument?

Example (watch the vertex labels): aTree = TreeGraph[{"a" -> "b", "a" -> "c"}, VertexLabels -> "Name"] ...
300 views

### Relaxation of Mass-Spring System with Pinned Masses

Problem Assume that four masses are connected to each other by springs while two of them are pinned down at their initial positions. Find the position of masses when system is at its minimum (...
1k views

### Combinatorica package and graph-theoretical issues

I've searched for a solution to my problem a couple of days, and I didn't find one. Hope you guys can help me. I'm currently trying to solve some graph-theoretical problems. One of them is to find ...
6k views

### Solving the Travelling Salesman Problem

I've been trying to find some kind of mathematical computer software to solve the Travelling Salesman Problem. The Excel Solver is able to do it, but I've noticed there is a built-in function in ...
79 views

### Powerset Animation/Invisible Vertices/Graph Layout

I wanted to visualize the cumulative powerset construction process and came up with two functions: ...
423 views

### Creating a hyperlink graph from Wikipedia

This goes out to all the Mathematica experts - I'm hoping to get some helpful comments, ideas or code for that matter. In my attempts to maximize learning efficiency I had the idea to create an (...
233 views

### Possible improvements to this Syracuse (3x+1)/2 graph?

This algorithm produces the Syracuse disjoint tree graph without any duplicates. No need for Union, For, and ...
60 views

### Unexpected behaviors with Edge Weights

Noticed some bizarre behavior when subgraphing on weighted graphs, which probably extends to graphs with arbitrary edge properties. I construct a weighted graph with five edges, defining a specific ...
277 views

### How to generate a random flow graph?

A flow graph is a rooted directed graph that the root reaches all other vertices. I need to generate a random flow graph in Mathematica. My idea is to use ...
328 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 ...
91 views

### Avoiding overlap in rendering of GraphPlot

I'm trying to visualize some 'graphs' (i.e. the mathematical objects with nodes and edges) using GraphPlot[]. I am defining the nodes using objects such as ...
219 views

I am using ...
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### How to visualize large graphs with directed edge bundling?

I'm wondering if anyone has implemented edge bundled graph plotting? An important paper is "Force-Directed Edge Bundling for Graph Visualization" by Danny Holten and Jarke J. van Wijk.
94 views

### Graph: Coloring Edges individually

CODE: Graph[{Style[0 -> 1, Red], Style[0 -> 1, {Blue, Dashed}]}] This mathematica code will make both lines solid Red, since they belong to the same two ...
83 views

### RandomGraph with specific constraints

I need to generate random connected simple graphs (no loops) with the constraint that exactly two vertices must only have a single edge. I can create many connected graphs (but very few will have the ...
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### Create graph K5, delete 2 edges and 2 vertex, create adjacency matrix [duplicate]

I need help about this problem. I should create graph K5, delete 2 edges and 2 vertex from it and from the new graph create adjacency matrix. I have poor knowledge and i don't need anyone to solve the ...
89 views

### DeleteVertex in Kpartite graph

How can i make K7,2 graph and how can i delete 2 vertex? Btw, i need to use package -> Combinatorica`; I tried this: ...
75 views

### Graph not drawing after VertexDelete

I'm very new to Mathematica and am currently trying the VertexDelete function, but after using it, my graph isn't drawing. Input: ...
86 views

### How to use the edge routing of LayeredDigraphEmbedding when specifying explicit vertex coordinates?

The "LayeredDigraphEmbedding" GraphLayout uses an edge routing algorithm which produces nice and readable diagrams and curved ...
355 views

### Drawing a graph with vertex avoiding edges? (Handling vertices that must be colinear?)

I'd like to draw something like the following graph: ...
152 views

### Can I make a simple game in Mathematica?

Here is the game outline: $\hspace{2.5cm}$ There is one player. The player ($\mathscr{L}$) moves from node to node limited by the directed arrows. As the player moves, $\mathscr{G}_{\Huge\cdot}$ ...
130 views

### Using NMinimize to solve the Multi Commodity Flow problem

I have the following optimization problem and I was hoping to solve it with NMinimize. Unfortunately, I don't get the desired result. I would like to get an optimal vector for $d_{e}$. This is how ...
59 views

### FindShortestPath does not work

The FindShortestPath doesn't work in this graph, can someone tel me what's wrong? ...
272 views

### How do I get the adjacency Matrix from a random graph [closed]

I am using the command g = RandomGraph[{8, 13}]; GraphPlot[g, VertexLabeling -> True] to plot a random graph with n nodes and l edges. Once the program has ...