free parameters under maximisation

Description

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

Usage

activePar(x, ...)
## Default S3 method:
activePar(x, ...)

Arguments

Details

Several optimisation 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 optimisation-related information.

Value

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

Author(s)

Ott Toomet

See Also

maxNR, nObs

Examples

# a simple 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)

Results