Set search volumeSource:
Set search volume
setSearchVolume(params, search_vol = NULL, reset = FALSE, ...) getSearchVolume(params) search_vol(params) search_vol(params) <- value
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".
If set to TRUE, then the search volume will be reset to the value calculated from the species parameters, even if it was previously overwritten with a custom value. If set to FALSE (default) then a recalculation from the species parameters will take place only if no custom value has been set.
setSearchVolume(): A MizerParams object with updated search volume.
getSearchVolume() or equivalently
search_vol(): An array (species
x size) holding the search volume
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
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 chosen 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.
search_vol argument is not supplied, then the search volume is
$$\gamma_i(w) = \gamma_i w^q_i.$$
The values of \(\gamma_i\) (the search volume at 1g) and \(q_i\) (the
allometric exponent of the search volume) are taken from the
q columns in the species parameter dataframe. If the
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 \(\gamma_i(w)\).