nlformula {lme4}

Manipulate a Nonlinear Model Formula

Description

Check and manipulate the formula for a nonlinear model, such as specified in nlmer.

Usage

  nlformula(mc)

Arguments

mc

matched call from the calling function, typically nlmer(). Should have arguments named

formula:

a formula of the form resp ~ nlmod ~ meform where resp is an expression for the response, nlmod is the nonlinear model expression and meform is the mixed-effects model formula. resp can be omitted when, e.g., optimizing a design.

data:

a data frame in which to evaluate the model function

start:

either a numeric vector containing initial estimates for the nonlinear model parameters or a list with components

nlpars:

the initial estimates of the nonlinear model parameters

theta:

the initial estimates of the variance component parameters

Details

The model formula for a nonlinear mixed-effects model is of the form resp ~ nlmod ~ mixed where resp is an expression (usually just a name) for the response, nlmod is the call to the nonlinear model function, and mixed is the mixed-effects formula defining the linear predictor for the parameter matrix. If the formula is to be used for optimizing designs, the resp part can be omitted.

Value

a list with components

"respMod"

a response module of class "nlsResp"

"frame"

the model frame, including a terms attribute

"X"

the fixed-effects model matrix

"reTrms"

the random-effects terms object

See Also

Other utilities: findbars, mkRespMod, mkReTrms, nobars, subbars