\name{gg} \alias{gg} \title{ Gabriel Graph} \description{ A Gabriel graph is one where the vertices are points and there is an edge between two points if the maximal ball between the points contains no other points. } \usage{ gg(x, r = 1, p = 2, usedeldir = TRUE) } \arguments{ \item{x}{ a matrix of observations.} \item{r}{ a multiplier on the ball radius.} \item{p}{ the value of p in the \eqn{L_p} distance.} \item{usedeldir}{logical. Whether to use the deldir package or not.} } \details{ places an edge between two points \eqn{i,j} if the ball centered between the points with radius \eqn{r d(i,j)/2} contains no other points. } \value{ an object of class igraph. In addition it contains the attributes: \item{layout}{ the data.} \item{r,p}{arguments passed to \code{gg}} } \references{ K.R. Gabriel and R.R. Sokal, A New Statistical Approach to Geographic Variation Analysis, Systemic Zoology, 18, 259-278, 1969 D.J. Marchette, Random Graphs for Statistical Pattern Recognition, John Wiley & Sons, 2004. } \author{ David J. Marchette} \seealso{ \code{\link{rng}}} \examples{ x <- matrix(runif(100),ncol=2) g <- gg(x) \dontrun{ plot(g) } } \keyword{ math }% at least one, from doc/KEYWORDS \keyword{ multivariate }% __ONLY ONE__ keyword per line