Construct Self-starting Nonlinear Models

Usage

selfStart(model, initial, parameters, template)

Arguments

model a function object defining a nonlinear model.
initial a function object, with three arguments: mCall, data, and LHS, representing, respectively, the expression on the right hand side of model, a data frame in which to interpret the variables in mCall and LHS, and a name, or expression, representing the variable to be used as the "response" in the initial values calculations. It should return initial values for the parameters on the right hand side of model.

NOTE: when a self-starting model is model function is used in nls, the response vector (corresponding to the left hand side of the nonlinear formula in nls) is made available in frame 1 under the name .nls.initial.response and can be referenced from within initial, as in the example section below.

parameters, template these arguments are included to keep consistency with the call to the generic function, but are not used in the default method. See the documentation on selfStart.formula.

Description

A method for the generic function `selfStart' for formula objects.

Value

a function object of class selfStart, corresponding to a self-starting nonlinear model function. An initial attribute (defined by the initial argument) is added to the function to calculate starting estimates for the parameters in the model automatically.

Author(s)

Jose Pinheiro and Douglas Bates

See Also

selfStart.formula

Examples

library(lme)
# `first.order.log.model' is a function object defining a first order
# compartment model 
# `first.order.log.initial' is a function object which calculates initial
# values for the parameters in `first.order.log.model'

# self-starting first order compartment model

SSfol <- selfStart(first.order.log.model, first.order.log.initial)

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