nlstimedist (version 1.1.4)

timedist: Fit the Franco model

Description

Fit the Franco model

Usage

timedist(data, x, y, r, c, t, ...)

Arguments

data

The data to be included in the model.

x, y

The x and y values in the data, where the y values are the proportions.

r, c, t

The starting parameters for the model.

...

Additional parameters to be passed to nlsLM.

Details

The nlsLM function is used instead of the nls function in order to use the Levenberg-Marquardt algorithm which is an extremely robust method of curve-fitting as it is able to switch between Gauss-Newton and gradient descent. This allows it to cope with far-off-optimal starting values. The standard nls function does not use Levenberg-Marquardt; it instead uses the Gauss-Newton type, the PORT routines and a partial linear fit.

Examples

# NOT RUN {
tdTilia <- tdData(tilia, x = "Day", y = "Trees")
model <- timedist(data = tdTilia, x = "Day", y = "propMax", r = 0.1, c = 0.5,
                  t = 120)
model

# }