pop (version 0.1)

dispersal: dispersal transfun

Description

Create a transfun object representing a relative probability of dispersal between patches. Typically used inside a call to transition

Usage

dispersal(value)
d(value)
is.dispersal(x)

Arguments

value

the (positive) exponential rate of decay of dispersal probabilities. Large values imply shorter range dispersal.

x

an object to be tested as a dispersal transfun object

Details

d() is a shorthand for dispersal(). The transfun object returned, when applied to a landscape object, produces a square symmetric matrix, with zero diagonal and off-diagonals giving the relative between patch dispersal probability. This implies that all individuals in the state will try to disperse. The fraction remaining in the patch depends on value. To have only some fraction try to disperse, a dispersal transfun can be multiplied by a probability transfun indicating the probability of attempting dispersal.

The relative dispersal probability is given by exp(-d * value), where d is the Euclidean distance between the origin and destination patch.

Examples

# these are equivalent
disp <- dispersal(3)
disp <- d(3)

is.dispersal(disp)