selfStart.default            package:nls            R Documentation

Construct Self-starting Nonlinear Models

Description:

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

Usage:

     selfStart(model, initial, parameters, template)

Arguments:

   model: a function object defining a nonlinear model.

 initial: a function object, taking three arguments: `mCall', `data',
          and `LHS', representing, respectively, a matched call to the
          function `model', a data frame in which to interpret the
          variables in `mCall', and the expression from the left-hand
          side of the model formula in the call to `nls'. This function
          should return initial values for the parameters in `model'.

parameters, template: these arguments are included for consistency with
          the generic function, but are not used in the `default'
          method. See the documentation on `selfStart.formula'.

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:

     # `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)

