1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
% Generated by roxygen2 (4.1.1): do not edit by hand
% Please edit documentation in R/games.R
\name{sample_dot_product}
\alias{dot_product}
\alias{sample_dot_product}
\title{Generate random graphs according to the random dot product graph model}
\usage{
sample_dot_product(vecs, directed = FALSE)
}
\arguments{
\item{vecs}{A numeric matrix in which each latent position vector is a
column.}
\item{directed}{A logical scalar, TRUE if the generated graph should be
directed.}
\item{\dots}{Passed to \code{sample_dot_product}.}
}
\value{
An igraph graph object which is the generated random dot product
graph.
}
\description{
In this model, each vertex is represented by a latent position vector.
Probability of an edge between two vertices are given by the dot product of
their latent position vectors.
}
\details{
The dot product of the latent position vectors should be in the [0,1]
interval, otherwise a warning is given. For negative dot products, no edges
are added; dot products that are larger than one always add an edge.
}
\examples{
## A randomly generated graph
lpvs <- matrix(rnorm(200), 20, 10)
lpvs <- apply(lpvs, 2, function(x) { return (abs(x)/sqrt(sum(x^2))) })
g <- sample_dot_product(lpvs)
g
## Sample latent vectors from the surface of the unit sphere
lpvs2 <- sample_sphere_surface(dim=5, n=20)
g2 <- sample_dot_product(lpvs2)
g2
}
\author{
Gabor Csardi \email{csardi.gabor@gmail.com}
}
\references{
Christine Leigh Myers Nickel: Random dot product graphs, a model
for social networks. Dissertation, Johns Hopkins University, Maryland, USA,
2006.
}
\seealso{
\code{\link{sample_dirichlet}}, \code{\link{sample_sphere_surface}}
and \code{\link{sample_sphere_volume}} for sampling position vectors.
}
\keyword{graphs}
|
