Questions about handling graphs in Mathematica, graph theory, graph visualization, GraphPlot, the built-in Graph type and the Combinatorica` package.
0
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15 views
Unexpected error message from GraphPlot evaluation
(Running MMA 9 on Mac OSX 10.8.3, MacBook Pro, 16GB RAM)
I am trying to display a graph with GraphPlot. I want a few of the edges to be purple, and the rest red. I figured out a way to do this that I ...
-1
votes
1answer
79 views
I want to draw a graph using a weighted Adjacency matrix
I have a weighted adjacency matrix as follows:
...
2
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0answers
83 views
Why my Mathematica 9.0.1 wont work with some samples of Mathematica in Graph Theory?
I updated my Mathematica recently to 9.0.1 cause the previous version was giving me freaky result especially in FindMinimumCostFlow and ...
-1
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0answers
76 views
I have problem with FindMinimumCostFlow and CostValue [closed]
I have following problem.In my optimized graph flow even if I specified the first EdgeCost but I still have the 5 for CostValue. How it could happen?
...
5
votes
1answer
119 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 ...
0
votes
0answers
33 views
1
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1answer
69 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 ...
0
votes
2answers
132 views
4
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2answers
95 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
...
12
votes
1answer
115 views
How can I conveniently call igraph through RLink?
Mathematica has lots of functions for working with graphs, but this functionality is not yet as mature as the igraph library. It is useful to have access to igraph from Mathematica, both for ...
9
votes
2answers
154 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 ...
2
votes
1answer
138 views
Isomorphisms for graphs with loops and multiple edges
I am working with graphs with multiple edges and loops, and I want to eliminate all isomorphic graphs from a long list I've generated. The FindGraphIsomorphism ...
11
votes
2answers
195 views
Listing subgraphs of G isomorphic to SubG
If I have an undirected graph G, how could I write a function in Mathematica to obtain a list of subgraphs of G that are isomorphic to some other undirected graph SubG?
I'd like to learn how to ...
2
votes
3answers
221 views
How to find all graph isomorphisms in FindGraphIsomorphism
I found the second definition of the function FindGraphIsomorphism not working.
Here's the definition Mathematica 8 gives:
...
5
votes
2answers
199 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 $G$ ...
5
votes
2answers
123 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 ...
1
vote
1answer
69 views
23
votes
1answer
371 views
Finding the likeliest path in a Markov process
With Mathematica 9, we have the addition of various processes, among which the discrete Markov process. Given a transition probability matrix m, such a process is ...
3
votes
0answers
83 views
shortest paths in probabilistically weighted edges? [duplicate]
I understand Mathematica can find shortest paths. However, is it also able to find the most probable paths? I mean this is a case where edges are given probabilistic wights (from 0 to 1) and the most ...
1
vote
1answer
55 views
How can I stop DiscreteMarkovProcess[] from relabeling vertices?
I'm attempting to calculate the mean first passage time between two vertices, $v_1$ and $v_2$, provided some undirected graph $G$. However, I noticed that running the following script:
...
1
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0answers
60 views
What algorithm is Mathematica using for FirstPassageTimeDistribution[]?
What algorithm is Mathematica 9 using for FirstPassageTimeDistribution[]? Is it attempting to use PseudoInverse[] on the ...
2
votes
1answer
224 views
GraphPlot only working when I evaluate twice
I have some code that builds a graph and some vertex coordinates, but when I evaluate it I get a message that the list of coordinates is not valid and the graph is not valid and it shows the output as ...
2
votes
2answers
155 views
Create a planar graph from a set of random points
A planar graph is a graph embedded in the plane in such a way that the edges intersect at vertices. This is an example of a planar graph:
g = GridGraph[{3, 3}]
...
5
votes
3answers
414 views
Random Geometric Graphs
I'm trying to implement an application which uses random geometric graphs in Mathematica, but it seems Mathematica lacks the functionality. I need the following functionalities:
Generate a set of ...
0
votes
2answers
52 views
How can I efficiently and uniformly sample the set of vertices a fixed edge-wise distance away from a chosen vertex?
I have a large graph $G$, which may be either directed or undirected. How would I use DepthFirstScan[] or BreadthFirstScan[] to ...
0
votes
1answer
93 views
0
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2answers
85 views
Draw network graph and get the coordinates of each node
I would like to draw an undirected graph by specifying the nodes and the edges among them. This is currently done by, for example:
...
2
votes
3answers
94 views
Drawing a complete graph of an ego network
I have an ego network (a network of a person (ego) and his friends). It is drawn with the ego at the center surrounded by the friends. It might be possible that all the friends are connected to each ...
2
votes
0answers
54 views
Fast calculation of commute distances on large graphs (i.e. fast computation of the pseudo-inverse of a large Laplacian / Kirchhoff matrix)
I have a large, locally connected and undirected graph $G$ with $\approx 10^4$ vertices and $\approx 10^5$ to $\approx 10^6$ edges. Moreover I can bound the maximum vertex degree as $Q_{max}$. I ...
4
votes
0answers
81 views
Counting paths of a certain length between a source and sink vertex
I have a graph $G$, which may be directed or not, and I was wondering if there was an efficient way of using, say, BreadthFirstScan[] and FindShortestPath[] to count the number of paths between some ...
5
votes
3answers
113 views
2
votes
0answers
79 views
Caching of Graph Graphics
In this answer, Simon Woods concludes that when you display an expression with head graph more than once, something is getting stored somewhere. I looked into it too and found out this only happens if ...
1
vote
1answer
86 views
How do I create a graph with randomly directed edges starting from a undirected graph?
I have an undirected graph $G$. How would I randomly assign directions to some fraction $p$ of the edges? How might I do this efficiently / quickly provided I have a large graph structure?
For ...
0
votes
2answers
173 views
How to specify VertexCoordinates as geographic coordinates of cities?
I have been very busy these days with giving the VertexCoordinates of the cities the geographic coordinates from ...
1
vote
1answer
78 views
How to get a list of 3-connected graphs?
I'd like to use GraphData to get a list of graphs with vertex connectivity at least 3. I know GraphData["Nonplanar", 6] gives ...
2
votes
1answer
70 views
double arrow in GraphPlot
Is it possible to combine two edges into one with a double arrow?
For example:
...
1
vote
0answers
35 views
What is the best way to save a large graph object, allowing it to be reloaded quickly in a new kernel?
I generated a very large graph, too large to simply display and manipulate with copy/paste operations. How can I somehow save the graph to a file to allow it to be rapidly reloaded after I quit out ...
5
votes
2answers
136 views
Graph does not evaluate some options when not displayed
How can I force Graph to evaluate all its options without actually displaying the graph itself?
Evaluating the following code ignores the ...
7
votes
1answer
163 views
Making FindShortestPath a little bit sloppy [duplicate]
I have a dense graph, and I'd like to find multiple "almost shortest" paths from a source vertex, $v_s$, to a sink vertex, $v_s$, on an undirected graph $G$. How can I repeatedly run ...
8
votes
2answers
286 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 ...
2
votes
0answers
50 views
How can I recover a graph from a graphical output in a notebook after resetting the kernel?
I have an old Mathematica notebook with an output for a graph structure $G$ I would like to recover. However, the routine for building up the graph is stochastic, so I can't simply rerun the code.
...
2
votes
2answers
146 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 ...
10
votes
1answer
174 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 ...
8
votes
3answers
439 views
How to plot layered graphs?
Given a directed acyclic graph, there is always a possibility to plot the graph as layers, where nodes always send edges into one direction (usually down), to successive layers, and never backwards. ...
4
votes
2answers
294 views
Finding face vertices from the face adjacency graph
I have a question about face adjacency graphs.
Suppose that I have an adjacency matrix
...
1
vote
1answer
83 views
Weighted Kirchhoff Matrix?
I have a weighted graph and I want its graph Laplacian matrix (what Mathematica calls the Kirchhoff matrix in the unweighted case). Is there an easy way to get this?
For example, the command:
...
2
votes
1answer
74 views
Determining whether two k-chromatic graphs are equivalent (not simply isomorphic) using IsomorphicGraphQ?
In a previous question of mine, I asked whether Mathematica's built-in routines could determine an isomorphism for two $k$-chromatic graphs, Determining whether two $k$-chromatic graphs are isomorphic ...
2
votes
1answer
63 views
Is it possible for me to explicitly specify a point list for SpatialGraphDistribution?
The function RandomGraph[SpatialGraphDistribution[n, r]] generates a random geometric graph over $[0,1]^2$ where vertices are connected if they are within a ...
19
votes
1answer
574 views
How to create regular (planar) graphs?
How to programmatically create and plot regular planar graphs with $k = 3, 4$ or $6$ (not hypercubes) and regular nonplanar graphs of $k = 8$ (see figure)? Note that what matters is the average ...
0
votes
1answer
47 views
How does SocialMediaData determine vertex size
How does SocialMediaData determine the size of graph vertices, e.g. on what does the vertex size depend in, say, a Facebook friend network graph?
