Filter.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/Filter.R
\name{Filter}
\alias{Filter}
\title{Filter Base Class}
\description{
Base class for filters. Predefined filters are stored in the
\link[mlr3misc:Dictionary]{dictionary} \link{mlr_filters}. A Filter calculates a score
for each feature of a task. Important features get a large value and
unimportant features get a small value. Note that filter scores may also be
negative.
}
\details{
Some features support partial scoring of the feature set:
If \code{nfeat} is not \code{NULL}, only the best \code{nfeat} features are guaranteed to
get a score. Additional features may be ignored for computational reasons,
and then get a score value of \code{NA}.
}
\seealso{
Other Filter: 
\code{\link{mlr_filters_anova}},
\code{\link{mlr_filters_auc}},
\code{\link{mlr_filters_carscore}},
\code{\link{mlr_filters_cmim}},
\code{\link{mlr_filters_correlation}},
\code{\link{mlr_filters_disr}},
\code{\link{mlr_filters_find_correlation}},
\code{\link{mlr_filters_importance}},
\code{\link{mlr_filters_information_gain}},
\code{\link{mlr_filters_jmim}},
\code{\link{mlr_filters_jmi}},
\code{\link{mlr_filters_kruskal_test}},
\code{\link{mlr_filters_mim}},
\code{\link{mlr_filters_mrmr}},
\code{\link{mlr_filters_njmim}},
\code{\link{mlr_filters_performance}},
\code{\link{mlr_filters_variance}},
\code{\link{mlr_filters}}
}
\concept{Filter}
\section{Public fields}{
\if{html}{\out{<div class="r6-fields">}}
\describe{
\item{\code{id}}{(\code{character(1)})\cr
Identifier of the object.
Used in tables, plot and text output.}

\item{\code{task_type}}{(\code{character(1)})\cr
Task type, e.g. \code{"classif"} or \code{"regr"}.

For a complete list of possible task types (depending on the loaded packages),
see \code{\link[=mlr_reflections]{mlr_reflections$task_types$type}}.}

\item{\code{task_properties}}{(\code{character()})\cr
\link[mlr3:Task]{mlr3::Task}task properties.}

\item{\code{param_set}}{(\link[paradox:ParamSet]{paradox::ParamSet})\cr
Set of hyperparameters.}

\item{\code{feature_types}}{(\code{character()})\cr
Feature types of the filter.}

\item{\code{packages}}{(\code{\link[=character]{character()}})\cr
Packages which this filter is relying on.}

\item{\code{man}}{(\code{character(1)})\cr
String in the format \verb{[pkg]::[topic]} pointing to a manual page for this object.
Defaults to \code{NA}, but can be set by child classes.}

\item{\code{scores}}{Stores the calculated filter score values as named numeric vector.
The vector is sorted in decreasing order with possible \code{NA} values
last. Tied values (this includes \code{NA} values) appear in a random,
non-deterministic order.}
}
\if{html}{\out{</div>}}
}
\section{Methods}{
\subsection{Public methods}{
\itemize{
\item \href{#method-new}{\code{Filter$new()}}
\item \href{#method-format}{\code{Filter$format()}}
\item \href{#method-print}{\code{Filter$print()}}
\item \href{#method-help}{\code{Filter$help()}}
\item \href{#method-calculate}{\code{Filter$calculate()}}
\item \href{#method-clone}{\code{Filter$clone()}}
}
}
\if{html}{\out{<hr>}}
\if{html}{\out{<a id="method-new"></a>}}
\subsection{Method \code{new()}}{
Create a Filter object.
\subsection{Usage}{
\if{html}{\out{<div class="r">}}\preformatted{Filter$new(
  id,
  task_type,
  task_properties = character(),
  param_set = ParamSet$new(),
  feature_types = character(),
  packages = character(),
  man = NA_character_
)}\if{html}{\out{</div>}}
}

\subsection{Arguments}{
\if{html}{\out{<div class="arguments">}}
\describe{
\item{\code{id}}{(\code{character(1)})\cr
Identifier for the filter.}

\item{\code{task_type}}{(\code{character()})\cr
Types of the task the filter can operator on. E.g., \code{"classif"} or
\code{"regr"}.}

\item{\code{task_properties}}{(\code{character()})\cr
Required task properties, see \link[mlr3:Task]{mlr3::Task}.
Must be a subset of
\code{\link[mlr3:mlr_reflections]{mlr_reflections$task_properties}}.}

\item{\code{param_set}}{(\link[paradox:ParamSet]{paradox::ParamSet})\cr
Set of hyperparameters.}

\item{\code{feature_types}}{(\code{character()})\cr
Feature types the filter operates on.
Must be a subset of
\code{\link[mlr3:mlr_reflections]{mlr_reflections$task_feature_types}}.}

\item{\code{packages}}{(\code{character()})\cr
Set of required packages.
Note that these packages will be loaded via \code{\link[=requireNamespace]{requireNamespace()}}, and
are not attached.}

\item{\code{man}}{(\code{character(1)})\cr
String in the format \verb{[pkg]::[topic]} pointing to a manual page for this object.
The referenced help package can be opened via method \verb{$help()}.}
}
\if{html}{\out{</div>}}
}
}
\if{html}{\out{<hr>}}
\if{html}{\out{<a id="method-format"></a>}}
\subsection{Method \code{format()}}{
Format helper for Filter class
\subsection{Usage}{
\if{html}{\out{<div class="r">}}\preformatted{Filter$format()}\if{html}{\out{</div>}}
}

}
\if{html}{\out{<hr>}}
\if{html}{\out{<a id="method-print"></a>}}
\subsection{Method \code{print()}}{
Printer for Filter class
\subsection{Usage}{
\if{html}{\out{<div class="r">}}\preformatted{Filter$print()}\if{html}{\out{</div>}}
}

}
\if{html}{\out{<hr>}}
\if{html}{\out{<a id="method-help"></a>}}
\subsection{Method \code{help()}}{
Opens the corresponding help page referenced by field \verb{$man}.
\subsection{Usage}{
\if{html}{\out{<div class="r">}}\preformatted{Filter$help()}\if{html}{\out{</div>}}
}

}
\if{html}{\out{<hr>}}
\if{html}{\out{<a id="method-calculate"></a>}}
\subsection{Method \code{calculate()}}{
Calculates the filter score values for the provided \link[mlr3:Task]{mlr3::Task} and
stores them in field \code{scores}. \code{nfeat} determines the minimum number of
features to score (see details), and defaults to the number
of features in \code{task}. Loads required packages and then calls
\code{private$.calculate()} of the respective subclass.
If the task has no rows, each feature gets the score \code{NA}.
\subsection{Usage}{
\if{html}{\out{<div class="r">}}\preformatted{Filter$calculate(task, nfeat = NULL)}\if{html}{\out{</div>}}
}

\subsection{Arguments}{
\if{html}{\out{<div class="arguments">}}
\describe{
\item{\code{task}}{(\link[mlr3:Task]{mlr3::Task})\cr
\link[mlr3:Task]{mlr3::Task} to calculate the filter scores for.}

\item{\code{nfeat}}{(\code{\link[=integer]{integer()}})\cr
THe minimum number of features to calculate filter scores for.}
}
\if{html}{\out{</div>}}
}
}
\if{html}{\out{<hr>}}
\if{html}{\out{<a id="method-clone"></a>}}
\subsection{Method \code{clone()}}{
The objects of this class are cloneable with this method.
\subsection{Usage}{
\if{html}{\out{<div class="r">}}\preformatted{Filter$clone(deep = FALSE)}\if{html}{\out{</div>}}
}

\subsection{Arguments}{
\if{html}{\out{<div class="arguments">}}
\describe{
\item{\code{deep}}{Whether to make a deep clone.}
}
\if{html}{\out{</div>}}
}
}
}