R: free parameters under maximisation

activePar {maxLik} | R Documentation

## 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

`x` | object, created by a maximisation routine, or derived from a maximisation object.
`...` | further arguments for methods

### 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)

[Package maxLik version 1.3-4 Index]