# Tagged Questions

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

186 views

### Figuring out how AbsoluteOptions works with Graphs

I am puzzled by how AbsoluteOptions works with Graph objects. I would have expected that one could use it to obtain all the ...
243 views

### Tom's family how to cross the bridge

A interesting question.Tom's family just have a flashlight which will extinguish after 30 seconds.They wanna go through a bridge to arrive opposite side with the flashlight.But as the picture,they ...
731 views

### Building graph based on the cities connection?

I built a Graph based on the permutations of city's connections from : ...
256 views

### Custom edge style (e.g. brush stroke, writing ink, etc.)

I would like to draw a graph with Mathematica in such a way that it looks like a handmade drawing or painting. To be more precise, is there a way to set a custom edge style such that it looks made ...
342 views

### Using Gather to rearrange my data

I have a list of elements: {{1, 2}, {1, 5}, {2, 6}, {3, 7}, {4, 8}, {5, 6}, {5, 9}, {9, 13}, {10,11}, {11, 12}, {11, 15}, {15, 16}} I have to divide it into ...
519 views

### Label multiple edges between same vertices

I have a simple graph with multiple edges between two vertices, say: Graph[{ Labeled[a -> b, "A"], Labeled[a -> b, "B"] }] Unfortunately, Mathematica ...
217 views

### NumberOfSpanningTrees command not working correctly

I am attempting to use the Combinatorica NumberOfSpanningTrees command for all n-cycle graphs from 3 to 30. I am trying to get a ...
1k views

### Drawing a graph with specified edge lengths

I was wondering if it was possible to ask Mathematica to draw a graph provided some set of vertices: $(v_1, ..., v_N) \in V$ connected by $M$ edges $(e_1, ..., e_M) \in E$, where the length of each ...
653 views

I'm looking for a robust way to add vertices to a graph by modifying its AdjacencyMatrix. Here's what I have so far: ...
193 views

### Algorithm used by IsomorphicGraphQ

I'd like to know which algorithm is used to test if two graphs are isomorphic?
321 views

### Preserving labels when using graph functions

I am finding that some functions that accept a graph and return a transformed graph lose all the vertex and edge labels of the graph being transformed. For example, when I define a graph like this: ...
668 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: ...
1k 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. ...
89 views

### Arrows from GraphicsComplex not converted to Normal form correctly

Bug introduced in 7.0 or earlier and persisting through 10.4.0 Show @ Graph[{1 -> 2, 2 -> 3}, Frame -> True] Normal @ % Is this a pure bug, or have ...
939 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 ...
780 views

### When using GraphPlot with an adjacency matrix, how can I make Mathematica draw exactly one self loop for any non-zero weight?

I have tried using the option MultiedgeStyle->None, but apparently Mathematica doesn't treat self loops in the same way it treats edges. For example, I find ...
444 views

### Removing edge weights from a Graph

How can I remove EdgeWeights from a Graph without affecting any other properties of the graph? Let's construct a graph with ...
327 views

### How can I efficiently check if a graph is unit distance?

A unit distance graph is a graph that is embeddable in the plane so that every edge has length 1. ...
192 views

### Issue with PathGraph

I am having a strange issue with PathGraph. Executing PathGraph[{a, b, c}] or ...
400 views

### Shortest tour with vertex priority

I changed the title of my question and tried to simplify formulation of the problem. I solve a very big vehicle routing problem. I divided this one big problem on many small sub-problems. Each small ...
350 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 ...
511 views

### Show path with arrows in a matrix

I have a matrix, for example, 5x5 matrix Partition[Range[25], 5]. And I am given a list, for example: ...
493 views

### Sierpinski carpet with GraphData

Is this graph in the list among the so-called "standard" structures used in GraphData? However, I have not found, yet, anything like "Carpet" or "Sponge" in the ...
2k views

### Dynamic graph visualisation using JLink/Java and GraphStream

Visualising the addition of new nodes and edges to a graph to 'watch it grow' is to something Mathematica is not suited to by default. However this type of animation really helps convey the emergence ...
307 views

### Multiple Forms of Transportation Between Cities

I want to be able to show different connections between cities based on modes of transportation. For instance, you could walk to any city, but it would take a long time, you could take a train, but ...
494 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 ...
1k views

535 views

### Graphing a network with state transition flows (of varying size)

In one of Stephen Wolfram's recent blog posts (http://blog.stephenwolfram.com/2013/04/data-science-of-the-facebook-world/#more-5350) he provides the network plot below. The size of the arrows that ...
252 views

### Self-loops in Graph may not display correctly or export correctly to PDF (due to BezierCurve problem)

Bug introduced in 10.0 and persisting through 10.3 Problem is due to a BezierCurve bug. I don't understand why the following does not work: ...
357 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 ...
336 views

### VertexSize doesn't scale with Graph layout?

I wonder about how I could make a Graph scale automatically when I vary the size of the vertices. I would like to visualize information with a ...
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 ...
1k views

### Can I use GoogleMap or other GPS data in creation of the Graphs?

I have following graph. ...
997 views

### How to add vertex/edge labels to existing graph

If I have already created a graph using Graph. Later, I want to add to the graph some vertex and/or edge labels, how can I do that? Thank you.
293 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 ...
348 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 ...
72 views

### Cannot set VertexCoordinates twice in a Graph. Workaround?

Versions 10.0-10.2 seem to have a bug when trying to set VertexCoordinates twice on a graph (version 9.0 is fine). Can you confirm it? What is a good workaround ...
138 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 ...
727 views

### How can I display a multigraph with different colored edges?

I'm new to Mathematica(version 9) and I'm trying to display a multigraph with different colored edges. Here's my code so far: ...
144 views

### How to get control over DepthFirstScan?

Is there a way to conditionally take control the flow during a depth-first scan against a TreeGraph? I have a tree graph whose nodes are constructed as object, and there's a method ...
93 views

### Set new edge capacity

Bug introduced in 9.0 or earlier and persisting through 10.3.1 I am trying to add a new edge to an existing graph and set its capacity, but for some reason the ...
437 views

### Is there a neat way to generate the odd set constraints matrix?

Given a undirected graph $G=(V,E)$, I am trying to generate a related matrix $M$, where columns are indexed by $E(G)$ and rows are indexed by all odd subsets of $V(G)$. I can finish this task using ...
688 views

### How can one draw a network with nodes and links in a grid shape?

I'd like to be able to use MMa's graphics to make something like this which I know must absolutely be possible (and probably easy) with MMa. I don't actually even need different colors (though ...
846 views

### Visualizing the output of a Voronoi diagram computation

I need to plot a graph (to be specific: Fortune Algorithm output) with given vertex coordinates and a few unconnected vertices. I am thinking of using Mathematica for that. ...
468 views

### How to remove all dead ends from a undirected graph?

so what I want to do is take an undirected graph, and remove all the "dead ends" (that is, vertices that are attached to only one other vertex), but do it in such a way that it does it until reaches ...
375 views

### Pairwise distances of points and classification using GraphDistanceMatrix

The challenge Given $n$ points in $\mathbf{R}^3$ and a cutoff distance, $d$, I would like to determine all pairs of points that are separated by less than the given cutoff distance, $d$, and all ...
529 views

### I can't understand FindShortest Tour

I can't understand the function FindShortestTour because of the result: FindShortestTour[{ {0, 1}, {5, 1}, {2, 1}, {10, 1}}] ...
245 views

### How to count all cliques (not just maximal ones) in graphs?

How can I count the numbers of $r$-cliques in a graph? In other words, the number of triangles, the number of $K_4$, the number of $K_5$ etc. I have tried for example ...