RoughSets (version 1.0-0)

FS.feature.subset.computation: The superreduct computation based on RST and FRST

Description

It is a function aimed as a wrapper of approaches calculating a superreduct. In other words, this function might produce only a feature subset which is not minimal.

Usage

FS.feature.subset.computation(decision.table,
    method = "greedy.heuristic.superreduct", ...)

Arguments

decision.table

a "DecisionTable" class representing the decision table. See SF.asDecisionTable.

method

a string representing the type of methods. See in Section Details.

...

other parameters corresponding to the chosen method.

Value

• A class "FeatureSubset".

  See FS.quickreduct.RST or FS.quickreduct.FRST.

Details

There exist three methods considered in this function as follows:

• "greedy.heuristic.superreduct": it is a greedy heuristic method which employs several quality measurements based on RST. SeeFS.greedy.heuristic.superreduct.RST.
• "quickreduct.frst": it is a feature selection function based on the fuzzy QuickReduct algorithm on FRST. SeeFS.quickreduct.FRST.
• "quickreduct.rst": it is a feature selection function based on the RST QuickReduct algorithm. SeeFS.quickreduct.RST.

These methods can be selected by assigning the parameter method. Additionally, SF.applyDecTable has been provided to generate the new decision table.

See Also

FS.quickreduct.RST.

Examples

###############################################################
## Example 1: generate reduct and new decision table using RST
###############################################################
data(RoughSetData)
decision.table <- RoughSetData$hiring.dt

## generate single superreduct
res.1 <- FS.feature.subset.computation(decision.table,
                  method = "quickreduct.rst")

## generate new decision table according to the reduct
new.decTable <- SF.applyDecTable(decision.table, res.1)

###############################################################
## Example 2: generate reduct and new decision table using FRST
###############################################################
data(RoughSetData)
decision.table <- RoughSetData$housing7.dt

## generate single superreduct
res.2 <- FS.feature.subset.computation(decision.table,
                  method = "quickreduct.frst")

## generate new decision table according to the reduct
new.decTable <- SF.applyDecTable(decision.table, res.2)