Defining a ProfileLikelihoodProblem

ProfileLikelihoodProblem type is designed to contain the necessary information to define a profile likelihood problem. For a comprehensive overview of the profile likelihood approach, please consult Raue, A. et al.

LikelihoodProfiler.ProfileLikelihoodProblemType
ProfileLikelihoodProblem{T,probType,P,PF,PR}

Defines a profile likelihood problem.

Mathematical Specification of a Profile Likelihood Problem:

A profile likelihood problem is defined by

  • an objective function (usually negative log-likelihood function) wrapped within an optprob::OptimizationProblem. Consult Optimization.jl docs for details.
  • a set of optimal values of the parameters optpars that minimize the objective function.

Constructors

ProfileLikelihoodProblem(optprob::OptimizationProblem, optpars::AbstractVector{<:Real},
  profile_range::Union{AbstractVector, Tuple} = tuple.(optprob.lb, optprob.ub); 
  conf_level::Float64 = 0.95, df::Int = 1, threshold::Real = chi2_quantile(conf_level, df))

Arguments

  • optprob::OptimizationProblem: The OptimizationProblem to be solved.
  • optpars::AbstractVector{<:Real}: Initial (optimal) values of the parameters.
  • profile_range::Union{AbstractVector, Tuple}: The range over which the profile likelihood is computed. A tuple (lower, upper) specifying a common profiling interval for all parameters, or an array of such tuples (one per parameter). By default, it uses the OptimizationProblem bounds for each parameter (i.e., tuple.(optprob.lb, optprob.ub)). (note!) If a parameter is not meant to be profiled, you may use nothing or infinite bounds.

Keyword arguments

  • conf_level::Float64: The confidence level for the profile likelihood. Defaults to 0.95.
  • df::Int: The degrees of freedom for the profile likelihood. Defaults to 1.
  • threshold::Real: The threshold for the profile likelihood. Can be set to Inf if confidence interval endpoint estimation is not required. Defaults to chi2_quantile(conf_level, df).
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