# Tagged Questions

igraph is a collection of software packages for graph theory and network analysis. Its core is a software library written in C/C++, and it has interfaces to GNU R and Python.

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### Community detection and modularity

I am reading the book "Network science" of Barabasi and in particular the chapter on community detection. If I understand correctly, modularity is a goodness factor of partition calculated by a ...
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### Problems with representing and analysing non-network data as a network?

Suppose I have a dataset with 200 observations of 30 categorical variables. The dataset describes websites and different kinds of design features they deploy (or do not deploy). If I were to convert ...
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### igraph shortest path export as vector [closed]

This is probably a very simple question but I cannot seem to solve it: I'm using the igraph package and want to export the vpath part of the get.shortest.paths output as a vector so that I may work ...
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### Does Newman clustering work on weighted graph with non-integer weights?

I have a weighted undirected graph, where weight is distance and it is between 0 and 1. I want to apply the weighted version of Newman clustering. I think weight must refer to strength or similarity, ...
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### How to create this graph in SIGMAPLOT

I'd like to ask 2 questions. 1. How to create this graph in SIGMAPLOT. I have tried it in several ways but didn't find the right one? 2. What model will be used for fitting to this data?
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### igraph betweenness depends on order of edges

I have a question whether order of edges in graph should matter or not? It seems that betweenness function produces slightly different results for different orderings of input file. input file : ...
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### How to create network(using igraph library) on google map with given weight of the edges, latitude and longitude

I want to display network of refugees in the world, its an undirected graph with given weighted of the edges, longitude and latitude of the two countries in a row. Data looks like as follows: ...
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### EdgeRank for eCommerce product feed

I am running my eCommerce store with around 1000 products with 10 categories. I want to show these products in feeds. But there are lots of products so its very complex to define priority list for ...
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### Negative modularity score calculated for detected communities in social network

I am trying to calculate the modularity score of a social network of 10 nodes using cluster_spinglass function to first detect probably community membership and ...
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### Graph clustering algorithms which consider negative weights

I have a graph instance with weighted directed edges which values can be in range [-1,1]. I need to do clustering on this graph, in order to find out groups in which vertices are more correlated. I ...
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### How to have an edge with a date attribute?

I have a question about fitting power-law distribution. I am working on a large graph and I have computed the distribution of vertex degrees. The Kolmogorov-Smirnov test rejects the fitting to a power-...
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### Validating Personalized Pagerank Matrix computation in R

My question is with reference to this paper here This is an excerpt from the paper From the similarity of the two equations we can see that if ppr_alpha_u is added up it will be equal to pr_alpha ...
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### Computing and validating personalised PageRank in R

I have been trying to calculate personalized pagerank matrix in R however I am facing some logical issues. As described by the paper by Archak et al found here, in section 5.2 the sum of the column i ...
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### Betweenness values for nodes different in SNAP and iGraph network analysis packages?

I compared results from using the SNAP (Stanford Network Analysis Project) Python library and the iGraph R library for analyzing networks. The betweenness values for nodes seem to be rather different ...
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### Should I use IN or OUT degree in Network Diffusion Model of Twitter network using iGraph?

I'm trying to run Independent Cascade Model for my Twitter graph to see who I have to stimulate to get the maximum cascade. This code is inspired by http://php.scripts.psu.edu/hxc249/code_segments/...
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### How to get to closest estimation of betweenness in large graph network using igraph?

I have a quite large graph of twitter followers. After importing, I have around 2 million nodes and 6 million edges. ...
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### Is it appropriate to use feedback centrality measures with directed networks?

I am analyzing adolescent friendship networks. I am trying to identify key players using different centrality measures, but I am not sure if it is right to use feedback centrality measures (...
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### Tying scale free network generation to the power law distribution

I am trying to understand how the link between the Barabasi-Albert graph generation and the scale-free networks it generates. Specifically, what is the mathematical relationship between the algorithm'...
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### Missing values with Community structure in networks?

Is there a way to predict Missing values with Community structure in networks? I have a data set with a couple dozen variables, such as age, level of education, self-assessed (via a Likert scale) ...
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### Search in a graph of medical records

I have a hierarchical order of a disease list. Just for example: Respiratory system disease 1.1. Asphyxia neonatorum 1.2. Croup 1.3. Lower respiratory tract disease 1.4. Bronchial disease 1....
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### techniques for sampling graphs? (possibly implemented in r packages)

Let's say I have a very large graph that proves impractical for visualization ends and I wanted to sample a random subgraph. (I know that I can filter out a subgraph via measures like degree, ...
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### In R: How do 'centralization' measures of the STATNET and iGraph package handle disconnected networks?

I am working with about 300 disconnected of different sizes. I calculate different graph-level centralization measures for these networks using the STATNET and iGraph packages in R. However, I find ...
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### What kind of model can I try to fit in this plot?

I have a plot like this. I wish to apply a model to this, however, I guess a linear regression model won't work on this. What I did was plot it on logarithm x and logarithm y axis as well but it ...
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### Plot directed acyclic graph with scaled edge length

I am trying to design a network (more precisely a directed acyclic graph) with specific edge lengths. The data is on the form of an edge list, and for each edge, there is an associated length. It ...
633 views

### Financial exposures modelling with graph theory tools

I was wondering how finance folks go about storing and modelling portfolio exposure relationships with the aim to later aggregate or slice & dice the exposures by different factor sets. For ...
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### How do multi-attribute edge-weights influence community detection?

My graph consists of a computer network topology where each vertex is a physical node/device (depicted using its IP address). Two vertices will have an edge if the nodes have had communication with ...
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### Centralization measures in weighted graphs

I'm using the igraph package in R to analyze network data. I'm currently trying to calculate some centrality measures for the ...
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### Force-directed methods to draw graphs

i am working to create a mapping of the adjacencies between 100 consumer goods. I have created an adjacency matrix based on product characteristics, and then create an i-graph of the graph/network (...
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### How to conduct community division of a social network with R?

I am trying to use R to conduct community division within my weighted network (based from an association matrix). I tried with igraph but I encountered some problems. I usually use the program Socprog ...