nlreg (version 1.2-2.2)

logLik.nlreg: Compute the Log Likelihood for Nonlinear Heteroscedastic Models

Description

Computes the log likelihood for a nonlinear model with possibly non constant variance.

Usage

# S3 method for nlreg
logLik(object, …)

Arguments

object

an object inheriting from class nlreg representing a fitted nonlinear heteroscedastic model.

…

absorbs any additional argument.

Value

Returns an object class logLik which is a number with attributes nobs, npar and df giving respectively the number of observations, the number of parameters (regression coefficients plus variance parameters) and the degrees of freedom in the model.

Details

This is a method for the function logLik() for objects inheriting from class nlreg.

See Also

rsm.object, logLik

Examples

# NOT RUN {
library(boot)
data(calcium)
calcium.nl <- nlreg( cal ~ b0*(1-exp(-b1*time)), 
                     start = c(b0 = 4, b1 = 0.1), data = calcium )
logLik( calcium.nl )
##
data(metsulfuron)
metsulfuron.nl <- 
    nlreg( log(area) ~ log( b1+(b2-b1) / (1+(dose/b4)^b3) ), 
           weights = ~ ( 1+dose^exp(g) )^2, data = metsulfuron, 
           start = c(b1 = 138, b2 = 2470, b3 = 2, b4 = 0.07, g = log(0.3)),
           hoa = TRUE )
logLik( metsulfuron.nl )
# }