Description Details Slots User-defined Criterion See Also
A virtual S4 class to store control parameters for model fitting.
RankControl class must be extended to reflect what distance metric should be used. Possibles extensions are RankControlWeightedKendall
. The control parameters that start with prefix EM_
are intended for the EM iteration. The ones with prefix SeachPi0
control the behaviour of searching model ranking.
EM_limit
maximum number of EM iteration
EM_epsilon
convergence error for weights and cluster probabilities in EM iteration
SearchPi0_limit
maximum number of iterations in the local search of pi0.
SearchPi0_FUN
a function object that gives a goodness of fit criterion. The default is log likelihood.
SearchPi0_fast_traversal
a logical value. If TRUE (by default), immediately traverse to the neighbour if it is better than the current pi0. Otherwise, check all neighbours and traverse to the best one.
SearchPi0_show_message
a logical value. If TRUE, the location of the current pi0 is shown.
SearchPi0_neighbour
a character string specifying which type of neighbour to use in the local search. Supported values are: "Cayley" to use neighbours in terms of Cayley distance or "Kendall" to use neighbours in terms of Kendall distance. Note that Kendall neighbours are a subset of Cayley neighbours
optimx_control
a list to be passed to optimx
. The list must not contain a component maximize=TRUE
since internally the negation of the likelihood function is minimized.
You can specify user-defined criterion to choose modal rankings. The function object SearchPi0_FUN takes a list as argument. The components in the list include the following. obs
: the number of observations.
w.est
: the estimated weights. log_likelihood
: the estimated log_likelihood. With this information, most of the popular information criterion can be supported and customized criterion can also be defined.
A larger returned value indicates a better fit. Note that if you are fitting a mixture model the EM algorithm always tries to maximized the log likelihood. Thus the default value should be used in this case.
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