Set external encounter rate

Usage

setExtEncounter(params, ext_encounter = NULL, ...)

getExtEncounter(params)

ext_encounter(params)

ext_encounter(params) <- value

Arguments

params: MizerParams
ext_encounter: Optional. An array (species x size) holding the external encounter rate. If not supplied, a default of 0 is used.
...: Unused
value: ext_encounter

Value

setExtEncounter(): A MizerParams object with updated external encounter rate.

getExtEncounter() or equivalently ext_encounter(): An array (species x size) with the external encounter rate.

Setting external encounter rate

The external encounter rate is the rate at which a predator encounters food that is not explicitly modelled. It is a rate with units mass/year.

The ext_encounter argument allows you to specify an external encounter rate that depends on species and body size. You can see an example of this in the Examples section of the help page for setExtEncounter().

Examples

params <- newMultispeciesParams(NS_species_params)
#> Because you have n != p, the default value for `h` is not very good.
#> Because the age at maturity is not known, I need to fall back to using
#> von Bertalanffy parameters, where available, and this is not reliable.
#> No ks column so calculating from critical feeding level.
#> Using z0 = z0pre * w_max ^ z0exp for missing z0 values.
#> Using f0, h, lambda, kappa and the predation kernel to calculate gamma.

#### Setting allometric encounter rate #######################

# Set coefficient for each species. Here we choose 0.1 for each species
encounter_pre <- rep(0.1, nrow(species_params(params)))

# Multiply by power of size with exponent, here chosen to be 3/4
# The outer() function makes it an array species x size
allo_encounter <- outer(encounter_pre, w(params)^(3/4))

# Change the external encounter rate in the params object
ext_encounter(params) <- allo_encounter