### From AIRWiki

## Contents |

## Install the package under R environmemnt

under Ubuntu install the R package:

`sudo apt-get install r-base-core`

type R to start the program:

`R`

type the command to download and install igraph as R library:

`install.packages("igraph")`

## Starting with the package

don't forget to load the library:

`library('igraph')`

parse a network file in Pajek format and access to its memory representation through the variable 'g':

`g <- read.graph(file='/your/path/.../file.net', format='pajek')`

list vertex and their attributes of graph g:

```
V(g) # the list of all nodes
V(g)[0] # access the first node
list.vertex.attributes(g) # the list of all vertex attributes names
V(g)[0]$id # access the attribute 'id' for the first node
```

list edges/arcs and their attributes of graph g:
```
```

```
```

```
E(g) # the list of all edges/arcs
E(g)[0] # access the first edge/arc
list.edge.attributes(g) # the list of all edges/arcs attributes names
E(g)[0]$weight # access the attribute 'weight' for the first node
```

draw the graph:
```
```

```
```plot(g)
tkplot(g)

```
```

## Macroscopic Analysis

**graph size** (number of nodes): length(V(g))

**number of edges**: length(E(g))

**diameter**: diameter(g)

**mean degree**:

**density**:

**giant component size** (the largest connected component size):

assortativity:

## Node Centrality Analysis

**degree**: degree(g)

**closeness**: closeness(g)

**betweenness**: betweenness(g)

**eigenvector**/**pagerank**: evcent(g)

## Clustering Techniques

**connected components**: clusters(g)

**edge betweenness**:

**walktrap**:

**spinglass**:

## References and further informations

Igraph/R documentation: http://igraph.sourceforge.net/doc/R/00Index.html