nlformula: Manipulate a Nonlinear Model Formula

In lme4: Linear Mixed-Effects Models using 'Eigen' and S4

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

lme4 documentation built on July 3, 2024, 5:11 p.m.