Define how population abundances are updated from one time step to the next. Functions can take any form but will only be vectorised across replicates in limited situations.
update_crossprod(pop, mat)
update_binomial_leslie(pop, mat)
update_multinomial(pop, mat)current state of the population
matrix of vital rates used to update population state
Updaters can be changed through the options
argument to simulate and can also be changed
globally for an R session by changing the global option with,
e.g., options(aae.pop_update = update_binomial_leslie)
update_crossprod updates abundances with a direct
matrix multiplication that does not include any form of demographic
stochasticity. This is the fastest update option and will vectorise
across replicates if the population matrix is not expanded by
environmental_stochasticity or
density_dependence.
update_binomial_leslie updates abundances
with a direct RNG draw that combines update with demographic
stochasticity, assuming a Leslie matrix.
update_multinomial updates abundances with a
direct RNG draw that combines update with demographic stochasticity,
allowing for general matrix forms (slower than
update_binomial_leslie).
# define a basic population
nstage <- 5
popmat <- matrix(0, nrow = nstage, ncol = nstage)
popmat[reproduction(popmat, dims = 4:5)] <- c(10, 20)
popmat[transition(popmat)] <- c(0.25, 0.3, 0.5, 0.65)
# define a dynamics object
dyn <- dynamics(popmat)
# simulate with the default updater
sims <- simulate(dyn)
# simulate with a multinomial updater
sims <- simulate(dyn, options = list(update = update_multinomial))