detfun0_sin {pttstability}

deterministic function with time-varying carrying capacity

Description

Simulates deterministic component of Ricker model, of the form xt+1 = xt exp(exp(sdet[1])*(1-xt/K)) where K varies with time as (sin(time/2)+exp(sdet[2])+0.5)*(2/3). Function is calibrated such that for exp(sdet[2]) = 1, mean(K) = 1.

Usage

detfun0_sin(sdet, xt, time = NULL, ...)

Arguments

sdet

a numeric vector of length two, specifying growth rate and carrying capacity

xt

a number or numeric vector of abundances at time t

time

the timestep - defaults to NULL (i.e. not used)

...

additional arguments, for compatability with other usages of the function - values are not used in this implementation

Value

a number or numeric vector of length xt, with predicted abundances at time t+1