make_guess_primary {biogrowth}  R Documentation 
Initial guesses for fitting primary growth models
Description
The function uses some heuristics to provide initial guesses for the parameters
of the growth model selected that can be used with fit_growth()
.
Usage
make_guess_primary(
fit_data,
primary_model,
logbase_mu = 10,
formula = logN ~ time
)
Arguments
fit_data 
the experimental data. A tibble (or data.frame) with a column
named 
primary_model 
a string defining the equation of the primary model,
as defined in 
logbase_mu 
Base of the logarithm the growth rate is referred to. By default, 10 (i.e. log10). See vignette about units for details. 
formula 
an object of class "formula" describing the x and y variables.

Value
A named numeric vector of initial guesses for the model parameters
Examples
## An example of experimental data
my_data < data.frame(time = 0:9,
logN = c(2, 2.1, 1.8, 2.5, 3.1, 3.4, 4, 4.5, 4.8, 4.7))
## We just need to pass the data and the model equation
make_guess_primary(my_data, "Logistic")
## We can use this together with fit_growth()
fit_growth(my_data,
list(primary = "Logistic"),
make_guess_primary(my_data, "Logistic"),
c()
)
## The parameters returned by the function are adapted to the model
make_guess_primary(my_data, "Baranyi")
## It can express mu in other logbases
make_guess_primary(my_data, "Baranyi", logbase_mu = exp(1)) # natural
make_guess_primary(my_data, "Baranyi", logbase_mu = 2) # base2
[Package biogrowth version 1.0.4 Index]