cluster: volume.ellipsoid – R documentation

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volume.ellipsoid

Compute the Volume (of an Ellipsoid)

Description

Compute the volume of geometric R object. This is a generic function and has a method for ellipsoid objects (typically resulting from ellipsoidhull().

Usage

volume(object, ...)
## S3 method for class 'ellipsoid'
volume(object, log = FALSE, ...)

Arguments

`object`	an R object the volume of which is wanted; for the `ellipsoid` method, an object of that class (see `ellipsoidhull` or the example below).
`log`	`logical` indicating if the volume should be returned in log scale. Maybe needed in largish dimensions.
`...`	potential further arguments of methods, e.g. `log`.

Value

a number, the volume V (or \log(V) if log = TRUE) of the given object.

Author(s)

Martin Maechler (2002, extracting from former clusplot code); Keefe Murphy (2019) provided code for dimensions d > 2.

Examples

## example(ellipsoidhull) # which defines 'ellipsoid' object <namefoo>

myEl <- structure(list(cov = rbind(c(3,1),1:2), loc = c(0,0), d2 = 10),
                   class = "ellipsoid")
volume(myEl)# i.e. "area" here (d = 2)
myEl # also mentions the "volume"

set.seed(1)
d5 <- matrix(rt(500, df=3), 100,5)
e5 <- ellipsoidhull(d5)

cluster

"Finding Groups in Data": Cluster Analysis Extended Rousseeuw et al.

v2.1.2

GPL (>= 2)

Authors

Martin Maechler [aut, cre] (<https://orcid.org/0000-0002-8685-9910>), Peter Rousseeuw [aut] (Fortran original, <https://orcid.org/0000-0002-3807-5353>), Anja Struyf [aut] (S original), Mia Hubert [aut] (S original, <https://orcid.org/0000-0001-6398-4850>), Kurt Hornik [trl, ctb] (port to R; maintenance(1999-2000), <https://orcid.org/0000-0003-4198-9911>), Matthias Studer [ctb], Pierre Roudier [ctb], Juan Gonzalez [ctb], Kamil Kozlowski [ctb], Erich Schubert [ctb] (fastpam options for pam(), <https://orcid.org/0000-0001-9143-4880>), Keefe Murphy [ctb] (volume.ellipsoid({d >= 3}))

Initial release

2021-04-16