Set search volume
setSearchVolume(params, search_vol = NULL)
| params | MizerParams |
|---|---|
| search_vol | Optional. An array (species x size) holding the search volume for each species at size. If not supplied, a default is set as described in the section "Setting search volume". |
MizerParams
The search volume \(\gamma_i(w)\) of an individual of species \(i\)
and weight \(w\) multiplies the predation kernel when
calculating the encounter rate in getEncounter and the
predation rate in getPredRate.
The name "search volume" is a bit misleading, because \(\gamma_i(w)\) does not have units of volume. It is simply a parameter that determines the rate of predation. Its units depend on your choice, see section "Units in mizer". If you have chose to work with total abundances, then it is a rate with units 1/year. If you have chosen to work with abundances per m^2 then it has units of m^2/year. If you have chosen to work with abundances per m^3 then it has units of m^3/year.
If the search_vol argument is not supplied, then the search volume is
set to
$$\gamma_i(w) = \gamma_i w^q_i.$$
The values of \(\gamma_i\) (the search volume at 1g) and \(q_i\) (the
allometric exponent of the search volume) are taken from the gamma and
q columns in the species parameter dataframe. If the gamma
column is not supplied in the species parameter dataframe, a default is
calculated by the get_gamma_default function. Note that only
for predators of size \(w = 1\) gram is the value of the species parameter
\(\gamma_i\) the same as the value of the search volume \(\gamma_i(w)\).
Other functions for setting parameters:
setBMort(),
setFishing(),
setInitial(),
setIntakeMax(),
setInteraction(),
setMetab(),
setParams(),
setPlankton(),
setPredKernel(),
setReproduction()
if (FALSE) { params <- newTraitParams() params@species_params$gamma[3] <- 1000 params <- setSearchVolume(params) }