phi
From untb v1.7-2
by Robin K S Hankin
Hubbell's phi
Hubbell's phi: counts of species abundances
- Keywords
- math
Usage
phi(x,addnames=TRUE)
unphi(freq, string="spp")
Arguments
- x
- Ecosystem vector; is coerced to class
count
- addnames
- Boolean with default
TRUE
meaning to set the name of the $i$th element to the species with abundance $i$ if unique. Set toFALSE
to suppress this, which is useful if the species names are long - freq
- Frequency data (eg as returned by
phi()
) - string
- Character; species name to prepend (using
NULL
can be confusing)
Details
Function phi()
coerces its argument to a count
object and
by default returns a named vector whose $i$th element is the
number of species with $i$ individuals. The name of the
$i$th element is the species with abundance $i$ if unique
and empty otherwise. Function phi()
is used by
theta.prob()
.
Function unphi()
does the reverse: given the output of
phi()
, it returns a corresponding count
object. Note that
species names are lost.
Note
The code for setting the names is a dog's breakfast
References
S. P. Hubbell 2001. The Unified Neutral Theory of Biodiversity. Princeton University Press.
See Also
Examples
jj <- c(rep("oak",5) ,rep("ash",2),rep("elm",3),"pine","tea","yew")
a <- as.count(jj)
phi(a)
unphi(phi(a)) #should match 'a' except for species names (which are lost)
data(butterflies)
phi(butterflies,add=FALSE)
summary(unphi(phi(butterflies))) #should match 'summary(butterflies)'
Community examples
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