# nlformula

##### Manipulate a Nonlinear Model Formula

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

the model frame, including a terms attribute

the fixed-effects model matrix

the random-effects terms object

##### See Also

Other utilities: `findbars`

,
`mkRespMod`

, `mkReTrms`

,
`nobars`

, `subbars`

*Documentation reproduced from package lme4, version 1.1-21, License: GPL (>= 2)*