maxLik (version 1.4-6)

activePar: free parameters under maximization

Description

Return a logical vector, indicating which parameters were free under maximization, as opposed to the fixed parameters that are treated as constants. See argument “fixed” for maxNR.

Usage

activePar(x, …)
# S3 method for default
activePar(x, …)

Arguments

x

object, created by a maximization routine, such as maxNR or maxLik, or derived from a maximization object.

…

further arguments for methods

Value

A logical vector, indicating whether the parameters were free to change during optimization algorithm.

Details

Several optimization routines allow the user to fix some parameter values (or do it automatically in some cases). For gradient or Hessian based inference one has to know which parameters carry optimization-related information.

See Also

maxNR, nObs

Examples

# NOT RUN {
## a two-dimensional exponential hat
f <- function(a) exp(-a[1]^2 - a[2]^2)

## maximize wrt. both parameters 
free <- maxNR(f, start=1:2) 
summary(free)  # results should be close to (0,0)
activePar(free)

## keep the first parameter constant
cons <- maxNR(f, start=1:2, fixed=c(TRUE,FALSE))
summary(cons) # result should be around (1,0)
activePar(cons)
# }