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

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7
votes
1answer
121 views

How to extract a Graph[] from an image?

This graph (as a picture) is given below: I am wondering rather than setting up this network graph using Mathematica syntax such as PathGraph,...
1
vote
2answers
153 views

Styling the edges of a graph according to the multiplicities of the edges

I used the following code to make a simple triangle, in which the nodes have different effects each other: ...
1
vote
1answer
69 views

calculate relationship between cause and effect (rows/columns/delta etc.) on tableform

I tried to enter this Excel (on the right of the picture) information to program. following these codes has been used: ...
6
votes
2answers
119 views

Delete vertices of degree 2 and rewire graph

I want to delete all vertices of degree 2 from a graph and rewire it. Given a graph like graphA, I want to obtain graphB. ...
12
votes
0answers
172 views

A question about weighted graphs

Bug introduced in 8.0 or earlier and persisting through 10.3 I need create a weighted graph with given data. Number of nodes: $53$ $\quad$ Number of edges: $91$ ...
1
vote
1answer
98 views

How to find a cycle with a property in a graph

Let's have a graph with this edge list: edgelist = {s -> 1, s -> 2, 1 -> 3, 2 -> 1, 2 -> 4, 3 -> 2, 3 -> t, 4 -> 3, 4 -> t}; I want ...
5
votes
1answer
106 views

How to create a MorphologicalGraph from MorphologicalBranchPoints

I want to select the morphological branch points of a thinned image to create a MorphologicalGraph like the one obtained by Pruning. I want to avoid the pruning step. How can I delete from the ...
0
votes
1answer
64 views

How to check if (u,v) and (v,u) edges are in a given directed graph

I have a graph and i want a module to run through all the edges of this graph and check whether (u,v) edge is in this graph and (v,u) edge is in another given graph.
2
votes
1answer
100 views

Visualisation of feedback loops in a directed graph

Here are the nodes (vertices) of my graph: ...
0
votes
0answers
35 views

Weighted graph vizualization [duplicate]

Is it possible to visualize a weighted graph, so lines on screen would reflect weight? I.e., be longer, or shorter depending on edge weight? Slight OT: which graph visualising libraries/tools can do ...
3
votes
2answers
122 views

Coloring network edges by weight using GraphPlot

Following up on a previous question about how to color the nodes (vertices) of a network (graph) according to a color scaling of a property of those nodes, I'm now asking basically the same thing ...
2
votes
2answers
75 views

DiscreteMarkovProcess: labelling of states

Related, but it seems like the respondents there misunderstood the question. The following errors as DiscreteMarkovProcess::invsm: ...
14
votes
1answer
160 views

IsomorphicGraphQ fails to recognize that two empty graphs are identical

Bug introduced in 9.0.1 or earlier and persisting through 10.4.0 Consider the following two graphs: ...
0
votes
1answer
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 ...
0
votes
0answers
58 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
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 ...
8
votes
2answers
218 views

Efficient solution for a discrete assignment problem with pairwise costs

Let's consider a simple graph with N vertices, and a corresponding set of N items. The goal of the problem is to assign every item to a vertex on the graph so that sum of a per-edge (that is item-...
2
votes
2answers
73 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: ...
5
votes
1answer
188 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
0answers
96 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}, {word,...
1
vote
1answer
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 ...
4
votes
1answer
285 views

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

Bug introduced in version 9.0 or earlier and fixed in 10.3 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 ...
3
votes
1answer
59 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 ...
1
vote
1answer
88 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
109 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 ...
4
votes
2answers
64 views

Graph: vary color/length vertextlabels based on frequency

In this example I use a small network of 5 words. ...
1
vote
2answers
119 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 ...
6
votes
1answer
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. ...
6
votes
0answers
72 views

Functionality of FindMaximumFlow

I know that the superseeded function NetworkFlow (needs Combinatorica) uses Goldberg-Tarjan's Push-Relabel-Algorithm but i cant find any information on Mathematica's built-in-function (...
1
vote
0answers
48 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:...
0
votes
0answers
77 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 ...
2
votes
1answer
105 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 ...
26
votes
2answers
2k views

Trying to Visualize a Collatz - The Collatz conjecture

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 a visual 3D adjacency graph of my ...
4
votes
1answer
85 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"] ...
4
votes
3answers
168 views

Graph generation from a non-paired edge list

The elements in e = {{6414, 6598, 6927}, {7, 1035, 2382, 6927}, …} are the graph nodes; for example, {6414,6598,6927} is ...
1
vote
1answer
77 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
422 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 (...
1
vote
0answers
53 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 ...
9
votes
1answer
232 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 ...
6
votes
1answer
391 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(...
1
vote
2answers
87 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 ...
6
votes
0answers
65 views

VertexDelete not working on graph with VertexWeight

Bug introduced in 10.0 and fixed in 10.3 Good afternoon, I have observed an "unexpected behaviour" with VertexDelete and a graph with vertex weights. This is a minimal working example: OK ...
6
votes
1answer
93 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
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 ...
3
votes
1answer
123 views
0
votes
0answers
40 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
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: ...
2
votes
2answers
74 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: ...
8
votes
1answer
218 views

Enforce graph symmetry

I am using ...