get initial parameter estimates
Usage
getInitial(object, data, ...)
Arguments
object
|
a formula or a selfStart model that defines a
nonlinear regression model
|
data
|
a data frame in which the expressions in the formula or
arguments to the selfStart model can be evaluated
|
...
|
optional additional arguments
|
Description
This function evaluates initial parameter estimates for a nonlinear
regression model. If data
is a parameterized data frame or
pframe
object, its parameters
attribute is returned.
Otherwise the object is examined to see if it contains a call to a
selfStart
object whose initial
attribute can be
evaluated.Value
A named numeric vector of starting estimates for the parameters. The
construction of many selfStart models is such that these "starting"
estimates are in fact the converged parameter estimates.Author(s)
Jose Pinheiro and Douglas BatesSee Also
nls
,nlsList
,selfStart
,
selfStart.default
,selfStart.formula
Examples
library(lme)
data(Puromycin)
PurTrt <- Puromycin[ Puromycin$state == "treated", ]
## check if the response should be vel or rate
getInitial( vel ~ SSmicmen( conc, Vm, K ), PurTrt )