inahull {alphahull} | R Documentation |
Determine whether a point belongs to the alpha-convex hull
Description
This function determines whether a given point p belongs to the α-convex hull of a sample.
Usage
inahull(ahull.obj, p)
Arguments
ahull.obj |
Object of class "ahull" returned by the funcion ahull . |
p |
Numeric vector with two components describing a point in the plane. |
Details
The complement of the α-convex hull of a sample is calculated by complement
. The function inahull
checks whether the point p belongs to any of the open balls or halfplanes that define the complement.
Value
in.ahull |
A logical value specifying whether the point p belongs to the α-convex hull. |
See Also
ahull
, complement
.
Examples
# Random sample in the unit square
x<-matrix(runif(100),nc=2)
# Value of alpha
alpha<-0.2
# alpha-convex hull
ahull.obj<-ahull(x,alpha=alpha)
# Check if the point (0.5,0.5) belongs to the alpha-convex hull
inahull(ahull.obj,p=c(0.5,0.5))
[Package
alphahull version 0.1
Index]