projectIGraph {SOMbrero} | R Documentation |
Compute the projection of a graph on a grid
Description
Compute the projection of a graph, provided as an
igraph
object, on the grid of the somRes
object.
Usage
projectIGraph(object, init.graph, ...)
Arguments
object |
a |
init.graph |
an igraph whose number of vertices is equal
to the clustering length of the |
... |
Not used. |
Value
The result is an igraph
which vertexes are the
clusters (the clustering is thus understood as a vertex clustering) and the
edges are the counts of edges in the original graph between two vertices
corresponding to the two clusters in the projected graph or, if
init.graph
is a weighted graph, the sum of the weights between the
pairs of vertices corresponding to the two clusters.
The resulting igraph object's attributes are:
the graph attribute
layout
which provides the layout of the projected graph according to the grid of the SOM;the vertex attributes
name
andsize
which, respectively are the vertex number on the grid and the number of vertexes included in the corresponding cluster;the edge attribute
weight
which gives the number of edges (or the sum of the weights) between the vertexes of the two corresponding clusters.
Author(s)
Madalina Olteanu olteanu@ceremade.dauphine.fr
Nathalie Vialaneix nathalie.vialaneix@inrae.fr
References
Olteanu M., Villa-Vialaneix N. (2015) Using SOMbrero for clustering and visualizing graphs. Journal de la Société Française de Statistique, 156, 95-119.
See Also
projectIGraph.somSC
which uses the results of a
super-clustering to obtain another projected graph. plot.somRes
with the option type="graph"
or plot.somSC
with the
option type="projgraph"
.
Examples
data(lesmis)
set.seed(7383)
mis.som <- trainSOM(x.data=dissim.lesmis, type="relational", nb.save=10)
proj.lesmis <- projectIGraph(mis.som, lesmis)
## Not run: plot(proj.lesmis)