Obtain a vector of growth increments and a vector of standard
deviations for each growth increment using the Schnute-Francis growth model.
The growth increment model is defined as:
Usage
get_growth_increment(
midpoint = seq(31, 91, 2),
ga = 40,
gb = 80,
galpha = 5,
gbeta = 1,
gshape = 5,
gcv = 0.5,
gobs = 1,
gdd = 0,
gmin = 0.01,
biomass = 1,
tau = 1
)Arguments
- midpoint
a
numericvector of length bin midpoints (mm).- ga
a
numericvalue for the reference size at which \(G_{\alpha}\) is defined (mm).- gb
a
numericvalue for the reference size at which \(G_{\beta}\) is defined (mm).- galpha
the \(G_{\alpha}\) parameter: growth increment at size
ga(mm).- gbeta
the \(G_{\beta}\) parameter: growth increment at size
gb(mm).- gshape
the shape parameter \(G_{\gamma}\) controlling the curvature of the growth curve.
- gcv
the process error parameter \(G_{CV}\) as a coefficient of variation.
- gobs
the observation error parameter \(G_{obs}\) (mm).
- gdd
the density-dependence parameter affecting growth.
- gmin
the minimum standard deviation of growth increment (mm).
- biomass
the biomass used for density-dependent growth calculations.
- tau
the time at liberty (years).
Value
a list containing a vector of growth increments and a vector of the standard deviation for each increment.
Examples
get_growth_increment()
#> $gi
#> [1] 9.4121968 8.2003974 7.1245802 6.1816937 5.3645346 4.6629129 4.0649177
#> [8] 3.5580479 3.1300777 2.7696267 2.4664700 2.2116536 1.9974796 1.8174151
#> [15] 1.6659657 1.5385371 1.4313013 1.3410743 1.2652088 1.2015025 1.1481208
#> [22] 1.1035326 1.0664570 1.0358200 1.0107182 0.9903896 0.9741899 0.9615722
#> [29] 0.9520711 0.9452895 0.9408874
#>
#> $sigma
#> [1] 4.811170 4.220382 3.699988 3.248589 2.862614 2.536866 2.265146 2.040815
#> [9] 1.857241 1.708130 1.587724 1.490923 1.413323 1.351203 1.301484 1.261655
#> [17] 1.229697 1.204002 1.183295 1.166577 1.153059 1.142123 1.133284 1.126157
#> [25] 1.120441 1.115893 1.112322 1.109574 1.107524 1.106071 1.105132
#>