projection {pop}

Deterministic projection

Description

Project a population dynamic model in discrete time, recording the number of individuals in each state at each time point.

Usage

projection(dynamic, population, timesteps = 1)

is.pop_projection(x)

## S3 method for class 'pop_projection'
plot(x, states = NULL, patches = 1, ...)

Arguments

dynamic

a population dynamic model of class dynamic

population

a dataframe or named vector of positive integers, giving the number of individuals in each state of dynamic. If a dataframe, it should have only one row (as in the examples below), or as many rows as patches in the metapopulation if a multi-patch landscape has been defined for dynamic (using landscape). If a multi-patch landscape has been defined for dynamic, but population has only one row or is a vector, this population will be duplicated for all patches in the landscape.

timesteps

a positive integer giving the number of time steps (iterations) over which to simulate the model

x

a pop_projection object, or an object to be tested as one

states

character vector naming the states in the dynamic object used to run the projection that should be plotted. By default all of them are plotted.

patches

vector of positive integers identifying the patches for which to plot the projections. By default only projections for the first patch are plotted.

...

further arguments passed to or from other methods.

Value

an object of class pop_projection

Examples

# set up a three-stage model
stasis_egg <- tr(egg ~ egg, p(0.6))
stasis_larva <- tr(larva ~ larva, p(0.4))
stasis_adult <- tr(adult ~ adult, p(0.9))
hatching <- tr(larva ~ egg, p(0.35))
fecundity <- tr(egg ~ adult, r(20))
pupation <- tr(adult ~ larva, p(0.2))

pd <- dynamic(stasis_egg,
              stasis_larva,
              stasis_adult,
              hatching,
              pupation,
              fecundity)

population <- data.frame(egg = 1200, larva = 250, adult = 50)

# simulate for 50 timesteps, 30 times
proj <- projection(dynamic = pd,
                   population = population,
                   timesteps = 50)

is.pop_projection(proj)

par(mfrow = c(3, 1))
plot(proj)