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

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6
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3answers
685 views

Graph adjacency matrix with unconnected nodes

I am trying to display a series of 9x9 adjacency matrices which represent directed graphs on a 3x3 grid. The issue I am running up against is this (compounded by that fact that I don't really know how ...
6
votes
2answers
323 views

Efficient setting of properties of multiple vertices in Graph

The functions SetProperty and PropertyValue can only set a single property of a single vertex, as far as I know. How do I set a ...
6
votes
1answer
141 views

Replacing graph nodes with matrices

I would like to label a graph with matrices. Suppose the graph is simple: And I have an array mats that contains the labels for vertices 1,2,3,4 (these are just random 0-1 matrices; ignore the ...
6
votes
1answer
224 views

Coloring edges of a graph according to their weight?

What's the simplest way to plot a graph with weighted edges, such that the color of the edge corresponds to the weight of the edge?
6
votes
2answers
140 views

Why the Mouse dragging response not as smooth as Locator

I am experimenting to use MouseDragged eventhandler to change the vertices positions of a triangle, it works, but not as smooth as using Locators. Is this the ...
6
votes
3answers
323 views

Flow in pipeline graph

I have pipeline directed graph which has one source and several sinks ...
6
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3answers
161 views
6
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3answers
437 views

How to extract edgeweights from a graph

I have a graph with weighted edges, and I'd like to obtain the edge weights of the edges in the graph. Is there a nicer way of doing this than getting the ...
6
votes
2answers
289 views

How to color edges of a graph which has multiple edges connecting certain vertices

I'm studying BIBD(Balanced Incomplete Block Design) and want to draw some graphs by coloring their blocks in different colors, respectively. A block is a collection of edges (or vertices). For ...
6
votes
1answer
593 views

How to turn a random graph into a matrix

I have constructed a random graph with Mathematica using the RandomGraph command. Now I would like to convert this graph to a matrix, but I don't know how. The ...
6
votes
1answer
669 views

How can I draw a polygon from a set of angles?

In recreational mathematics, polytans are polygons formed by edge-connecting isosceles right triangles. Order-n polytans are those constructed from n such triangles. My question is this: Given a ...
6
votes
2answers
250 views

Truncate TreeForm to show only the top

For some expressions, TreeForm may grow very long. I'm only interested in the top levels of the expression. How can I get the tree form of only the first levels an ...
6
votes
1answer
162 views

Fractal dimension of a large networked molecular system

I am trying to determine the fractal dimension of this complex biomolecule (figure attached). Any clues as to how this can be done. In trying to determine this quantity, I wonder how its ...
6
votes
1answer
205 views

Generating a (random) 2-dimensional cellular network

I want to generate a network of random cells like the following picture: The general idea is to generate some random points (x,y) as coordinate of a vertex and then randomly choose some of these ...
6
votes
3answers
348 views

Export Graph to PDF

I know that I exported Graphs to PDFs before but it doesn't seem to work any more. I tried K5 = GraphData[{"Complete", 5}] Export["K5.PDF", K5] And I get a PDF ...
6
votes
1answer
249 views

What algorithm is Mathematica 9 using for “SpectralEmbedding” of graphs?

When I specify that a graph should be realized using the "SpectralEmbedding" procedure, what paper / algorithm for spectral embedding is this based on? I was unable to find any documentation for ...
6
votes
1answer
243 views

How to view all graphs available in GraphData?

Is there a "gallery" view of all the graphs available in GraphData? I realize that some graphs may not lend themselves to such representation (e.g. some may have ...
6
votes
3answers
218 views

Enumerate the 1-factors (perfect matchings) of $K_n$

Introduction I would like to enumerate the 1-factors, or (near-)perfect matchings, of the complete graph Kn. The adjacency list representation for Kn is basically { (x, y) | 1 ≤ x < y ≤ n }. For ...
6
votes
2answers
262 views

Flow/graph-based programming in Mathematica?

Is it possible in Mathematica to write a program inside a graph? For example if you have a bunch of different If[] statements that you need to embed within one ...
6
votes
2answers
242 views

Visualize the output of Trace in a tree structure

The output of Trace[expr] can be nicely represented as a tree, I guess. Here is an example trace. ...
6
votes
1answer
344 views

How to determine edgeweights from width of skeleton using MorphologicalGraph (or workaround)?

Background I'm trying to create a workaround for what seems to be a bug in MMA's graph functions related to edge weights: SO: How to Label Graph Edges with their weights According to MMA's ...
6
votes
1answer
218 views

Shortest polygonal path

I'd like to find the shortest distance between some points (every point must be visited), such as between these 3 points: ...
6
votes
1answer
128 views

Tooltip not working in web deployed cdf

I deployed a CDF file in a web page. I used both Mouseover and Tooltip functions. They both work in the raw CDF file. The ...
6
votes
2answers
255 views

How do I reorder vertices in a graph?

I have a directed acyclic graph $g$, and I'd like to re-order the vertices in this graph object such that when I call VertexList[myGraph] the vertices appear in ...
6
votes
1answer
153 views

Property assignment on a graph vertex using PropertyValue does not work inside a function

I created this function: AddStone[board_Graph, v_, s : white | black | empty] := PropertyValue[{board, v}, VertexState] = s This function should change the ...
6
votes
1answer
82 views

Setting PropertyValue for VertexWeight is not persistent

g = CompleteGraph[8, VertexSize -> Medium]; PropertyValue[{g, VertexList[g][[1]]}, VertexWeight] = 10; PropertyValue[g, VertexWeight] ...
6
votes
1answer
823 views

Ordering vertices with minimum Edge Crossing in Circular Graphs

Weighted and sorted Mathematica circular graphs are shown below. My question is how to reorder the vertices in such a way that they have minimum cuts (intersection of edges) while keeping the circular ...
6
votes
1answer
146 views

Vertices, their labels, and how to refer to them?

In the examples I have seen, graph vertices in Mathematica are usually explicit small integers. However, Wolfram documentation says that vertices can be any arbitrary expression (eg., george, x^2, ...
6
votes
1answer
301 views

Connect neighbouring points as list of segments in 2 D

Context I am interested in connecting neighboring points in 2/3D as list of segments. I am guessing this is something within the reach of graph theory, which is well implemented in mathematica. ...
6
votes
1answer
161 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: ...
6
votes
1answer
373 views

Interactive Graph Editing with Animation

I want to make a simple interactive user interface like this: Such that when the user clicks on the "Add Edge" button, the edge specified by from and to fiels is added to the graph. The new graph ...
6
votes
0answers
92 views

HighlightGraph and Hyperlink

In the documentation of Mathematica it is mentioned that you can use Hyperlink and Tooltip as wrapper in a similar manner as ...
6
votes
0answers
124 views

Is there a function to generate a minimal clique cover?

This is a graph problem known as the "Clique Edge Cover" or "Intersection Number" problem, and the goal is to find, from a given graph like $E=\{\{a,b\},\{a,c\},\{b,c\},\{b,d\},\{c,d\}\}$ and ...
5
votes
3answers
574 views

Graph and Markov Chain

I have the following code: proc = DiscreteMarkovProcess[1, {{0.6, 0.4}, {0.3, 0.7}}] Graph[{"A", "E"}, proc, GraphStyle -> "DiagramBlue"] How can I 'force' ...
5
votes
3answers
1k views

Travelling salesman with start and end points for 30 points

I am doing a route optimisation for delivery vehicles and failing dismally. Please see problem statement below. My current solution uses FindShortestTour, but this does not have defined start and end ...
5
votes
3answers
596 views

How to create a planar graph from a set of random points

Question Given a set of points in the plane, how can you create a planar graph in the standard graph representation of Mathematica (version 9 or higher), from these points? Background A planar ...
5
votes
3answers
206 views

Enumerating all connected graphs with 9 vertices

The version of my Mathematica is 10. I generate a connected graph with 9 vertices, but find that it is not included in Mathematica. ...
5
votes
3answers
480 views

How to display edge labels above edges?

The following code shows that edge labels "cover" edges in GraphPlot3D ...
5
votes
3answers
176 views

StandardForm on Graph edges

The Graph command displays edge labels in TraditionalForm. I instead want to use ...
5
votes
2answers
115 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 ...
5
votes
3answers
191 views

Converting expressions to “edges” for use in TreePlot, Graph

This question is similar to this: Nested list to graph. How to "flatten" an arbitrary expression, eg expr = a[b[c, d[e][f], g], h] to a list of key-value pairs ...
5
votes
3answers
332 views

Rendering polygon as graph with directed edges in Mathematica

In Mathematica I'm trying to render a polygon as a set of vertices and directed edges. What I have so far: ...
5
votes
2answers
157 views

Graph expansion on Mathematica

Is there a way by which Mathematica can be given a graph as an input and be asked to find its expansion? Note: By "expansion" I mean the quantity called "isoperimetric number" or "Cheeger constant", ...
5
votes
2answers
142 views

Improving performance in the generation of random (directed acyclic) graphs

I need to generate large (directed, acyclic, transitive) graphs. My code in Mathematica gets very slow for large numbers of vertices. I've tried a number of approaches and I can't find any significant ...
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 ...
5
votes
3answers
99 views

GraphIntersection Problem

I Have a problem when plotting 2 functions. I want to find out where the two graphs intersect eachother. That said, I want the coordinates (x, y) of the point. ...
5
votes
1answer
134 views

How to impose control over vertex-to-vertex Graph edges?

I’m working on a Markov Chain and hope there is a way to impose control over how Mathematica places edges to connect vertices in a Graph. My Markov Chain currently consists of 4 vertices with 2 of the ...
5
votes
1answer
483 views

How to display each step of an A star algorithm?

I wrote a pathfinding program: A*, which is an extension of Dijkstra. I want to see the result of each step at a time. Which function should I use? The main program is the notebook Astar, which is ...
5
votes
2answers
347 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 ...
5
votes
3answers
330 views

Centrality measures for single nodes

I am producing a graph, generated by a list of adjacent nodes. (The list looks like {1 ->583, 1->2977, 2->14, 4->1293, 5->221, ...}. Each node of my ...