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

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1answer
538 views

Adding an image background to a graph that uses vertexposition

Hello Mathematica stackexchange community! I need your help on a research project. I'm looking to create a graph g with vertices in specifies places and then use an image I have as the background of ...
1
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1answer
144 views

How can I change the Graph required data such as EdgeWeight,VertexWeight,EdgeCapacity,VertexCapacity in the Graph?

I asked this question in different form and because I couldn't receive the proper answer so I have to change my question.I know that was my fault sorry.I need to change the Matrix Data of nodes and ...
10
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4answers
598 views

Ordering vertices in GraphPlot

I'm new here, so forgive me if this question is not well-posed/duplicates an earlier question - although I've searched for similar questions without success. I'm trying to present a plot of ...
7
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2answers
474 views

HighlightGraph with different styles

I want to highlight two different directed paths on a graph with two different style. I am using the following two code snippets: ...
6
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3answers
631 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
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2answers
640 views

Coloring edges in GraphPlot

I'm a little stuck with graph drawing part of my research — I can't use the Graph function for plotting my graphs, because my graph is a multi-graph. ...
5
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2answers
214 views

Is there something wrong with VertexConnectivity

As I noticed in the documentation VertexConnectivity is defined as the following The vertex connectivity of a graph $g$ is the smallest number of vertices whose ...
22
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3answers
2k 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 ...
29
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8answers
2k views

Longest path in 0/1 matrix

I have a matrix of 0's and 1's forming a number of disjoint paths:   I would like to find the lengths of the paths, and from that "spectrum," the longest length (in the above example: 27, ...
16
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2answers
645 views

How to measure segment length and branch angle

I am trying to measure segment length and branch angle or bifurcation angle between each pair of segments. My image after thinning looks like this: ...
16
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3answers
1k views

Creating diagrams for category theory

Lately I've been doing algebra and I have found myself drawing a bunch of diagrams when I attempt to solve a problem. Most of the diagrams are very simple so I thought, I bet I can do this in ...
18
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1answer
419 views

How to visualize large graphs with directed edge bundling

I'm wondering if anyone has implemented edge bundled graph plotting? http://www.win.tue.nl/~dholten/papers/forcebundles_eurovis.pdf
14
votes
2answers
557 views

How can I speed up the classic GA for graph coloring?

I'm trying to compute the chromatic number of this graph (which is 28): g = Import@"http://www.info.univ-angers.fr/pub/porumbel/graphs/dsjc250.5.col"; My genetic ...
12
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2answers
1k views

How to convert an image to a graph and get the positions of the edges?

I am trying to convert an image to a graph. My image is already skeletonized and looks pretty much like this: What I need to do is identify all vertices and edges, and in particular get a list of ...
11
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1answer
329 views

Dynamic visualization of Graph[] on a webpage

How can we embed a dynamic version of a Graph object on a web page, similar to the one showcased on the networkx home page? This sort of dynamic visualization can ...
10
votes
1answer
578 views

Roads network visualization by thickness and color intensity by population from GIS files

We can have road networks of the countries in GIS shape file.For exmple from here. Normally traffic flows are proportionate to populations of the cities. I wonder how we can have the same in ...
16
votes
3answers
455 views

How to get complete Documentation Center graph of guide pages?

On the very last image below you can see a typical path of walking through Documentation Center guide pages. What is the best way to get the graph data and visualize the whole structure of these ...
13
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3answers
638 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 ...
12
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2answers
499 views

Calculating morphometric properties

Is it possible to calculate segment length, segment diameter and branch angles for three dimensional geometry. Geometry contains vertex points and polygon surfaces as ...
6
votes
1answer
267 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. ...
20
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1answer
870 views

Graph vs GraphPlot

What is the difference (in purpose) between Graph and GraphPlot? Which function is bested suited to which tasks? Background: I ...
15
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3answers
238 views

What is the most convenient way to change options for Graph[] objects?

What is the most convenient way to change options such as VertexLabels in existing Graph objects? (Version 7 users note: ...
7
votes
1answer
361 views

How to visualize the structure of this dynamic programming code

I am studying Mr. Wizard's answer to this question which tries to identify elementary circles in a graph. That answer uses dynamic programming technique to simplify the code. The underlying guideline ...
7
votes
4answers
313 views

Can I stop edges in graphs from drawing on top of the vertices?

Consider the following testadj = RandomVariate[BernoulliDistribution[0.15], {50, 50}]; AdjacencyGraph[testadj, VertexSize -> Large] The nodes are almost ...
17
votes
2answers
366 views

Packed Graph or GraphPlot output with non-square layout?

Graph or GraphPlot produce square layouts for disconnected graphs: Graph[Table[i -> Mod[i^3, 100], {i, 1, 100}]] I´d like to get a rectangular layout with ...
13
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4answers
444 views

How to recompute the layout of a Graph?

I asked a question about changing Graph properties in a similar way to how Show can change ...
9
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2answers
314 views

Transition between graphs

I want to visually demonstrate the manipulations made to a graph. For instance, I have a graph g where using the command ...
5
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3answers
240 views
5
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2answers
268 views

Is there something akin to “SubgraphIsomorphismQ” in Mathematica 9?

Provided two unlabeled graphs, $G$ and $H$, I would like to test where $H$ is a subgraph of $G$. In other words, I'd like to test whether we can prune some fixed number of vertices or edges from $G$ ...
1
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1answer
208 views

Display a labeled multigraph

Despite the integration of graphs and networks, multigraphs are not supported in Mathematica 8+. In Mathematica 9+, GraphPlot misbehaves for multigraphs having ...
14
votes
1answer
389 views

When to use built-in Graph/GraphPlot vs. Combinatorica

What are the pros and cons of using built-in Graph/GraphPlot (and related) types vs. types in the Combinatorica package?
12
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1answer
194 views

Layout a second graph of the same nodes in the same way

I have a number of graphs with the same nodes. I would like to be able to somehow save the layout that results from the spring embedded results of one graph (the first image), and have the other ...
9
votes
3answers
384 views

FindShortestTour for charity (or: How can I optimize meal delivery with FindShortestTour?)

I've been wondering about this for a while - but never got around to asking - until I saw faleichik's incredible answer to Mathematica Minecraft. I did some work at a not-for-profit a little while ...
9
votes
2answers
260 views

Determining whether two $k$-chromatic graphs are isomorphic (respecting vertex coloration)

Consider the case where I have two $k$-chromatic graphs $G_1$ and $G_2$, i.e. two graphs where individual vertices can be colored with one of a set of $k$ total colors, and I would like to determine ...
8
votes
2answers
472 views

Extracting vertex coordinates from an automatically laid out graph

Given a Graph with an automatically computed layout (i.e. not explicitly given VertexCoordinates, but using a ...
6
votes
3answers
290 views

Flow in pipeline graph

I have pipeline directed graph which has one source and several sinks ...
5
votes
1answer
412 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
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2answers
356 views

How to add new nodes to an existing graph with fixed (coordinates) nodes?

I'm ultimately trying to create a directed graph with some of the nodes in fixed positions and the other nodes placed around them in "acceptable" positions. It's better if I ask the question by ...
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
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
1answer
223 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 ...
5
votes
1answer
1k views

When do I use Mathematica, when do I use Gephi, and how do I use them together?

Mathematica has great operations for analyzing graphs but when the graphs are a bit bigger, Gephi seems to be more efficient (at least on my computer) at drawing and analyzing, i.e. visualizing the ...
3
votes
3answers
324 views

Generating a graph where vertices correspond to points in an integer lattice and edges connect points less than a threshold distance apart

I'd like to automatically generate a graph where vertices correspond to (and have the coordinates of) points in an $A \times B$ integer lattice, and a graph is generated by connected vertices within a ...
3
votes
2answers
219 views

Showing a forest with root of the trees on the top

I have a Graph object that contains a forest with directed trees. I want to draw the forest such that the root of the trees are on the top and the leaves are on the bottom. If I use the following line ...
9
votes
1answer
154 views

Algorithm used by IsomorphicGraphQ

I'd like to know which algorithm is used to test if two graphs are isomorphic?
7
votes
2answers
327 views

Convert Graph to Graphics

In Mathematica 9, a graph is returned as an object with head Graph: In[8]:= CompleteGraph[8] // Head Out[8]= Graph ...
7
votes
1answer
860 views

Dynamic Graph visualization

I'm working on a C++ library that will be used to construct and study certain graphs (as in a set of connected vertices, not a function plot). These graphs will be dynamic in nature (and can ...
6
votes
2answers
275 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
541 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
1answer
145 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 ...