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

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9
votes
1answer
129 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 ...
10
votes
2answers
197 views

Finding the minimum vertex cut of a graph

Bug introduced in 9.0.1 or earlier and fixed in 10.2.0 Note: FindVertexCut is new in 9.0. It seems that Mathematica is not correctly finding the smallest set of ...
6
votes
0answers
51 views

VertexDelete not working on graph with VertexWeight

Bug introduced in 10.0 and persisting through 10.2.0 Good afternoon, I have observed an "unexpected behaviour" with VertexDelete and a graph with vertex weights. This is a minimal working example: ...
11
votes
1answer
85 views

Question about TransitiveReductionGraph

Bug introduced in 10.0 and persisting through 10.2.0. Note: TransitiveReductionGraph is new in 10.0. In Mathematica 10.0 and 10.1, according to the ...
0
votes
1answer
32 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 ...
0
votes
0answers
35 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 ...
2
votes
1answer
39 views

Count graphs with fixed number of vertices incluing isomorphisms

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 ...
2
votes
1answer
60 views

Finding nonequivalent 3-cycles and edges of a given graph

So I have three graphs defined by the following nested list, I'm using this list notation instead <-> notation because it is more convenient for another part ...
5
votes
1answer
135 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 ...
2
votes
2answers
52 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: ...
2
votes
0answers
66 views

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}, ...
1
vote
1answer
36 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 ...
4
votes
1answer
217 views

Why don't the arrowheads show for this directed graph?

It's very weird, but the first graph is shown as undirected (dots connected by lines, not arrows. The second is shown as directed, with arrows. I'm using the cloud version of Mathematica. ...
1
vote
0answers
71 views
3
votes
1answer
27 views

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 ...
0
votes
1answer
42 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: ...
4
votes
2answers
74 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 ...
0
votes
2answers
60 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 ...
4
votes
2answers
56 views
6
votes
1answer
92 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. ...
1
vote
1answer
100 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 ...
1
vote
0answers
42 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 ...
0
votes
0answers
56 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 ...
22
votes
2answers
1k views

Trying to Visualize a Collatz - The Collatz conjecture

So I'm new in this and learning--- and I happen to have this collatz collatz[x_, y_] := If[x == 3*y || x == 2*y + 1 || y == 3*x || y == 2*x + 2, 2, 0] So i want ...
5
votes
1answer
134 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 ...
2
votes
1answer
382 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 ...
2
votes
1answer
183 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 ...
4
votes
1answer
56 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"] ...
9
votes
2answers
236 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 ...
12
votes
2answers
975 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 ...
16
votes
2answers
4k 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 ...
1
vote
1answer
67 views

Powerset Animation/Invisible Vertices/Graph Layout

I wanted to visualize the cumulative powerset construction process and came up with two functions: ...
8
votes
2answers
286 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 ...
8
votes
2answers
314 views

Is there a bug in FindClique?

If h is a graph, FindClique[g, {n}] should return a clique on exactly $n$ vertices if one exists in ...
9
votes
1answer
224 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 ...
1
vote
0answers
35 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 ...
7
votes
0answers
193 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 ...
1
vote
1answer
243 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 ...
1
vote
2answers
54 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 ...
8
votes
1answer
198 views
23
votes
1answer
593 views

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.
6
votes
1answer
76 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 ...
5
votes
1answer
58 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 ...
0
votes
0answers
39 views

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 ...
2
votes
1answer
81 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: ...
2
votes
2answers
65 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: ...
3
votes
1answer
74 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 ...
6
votes
3answers
218 views