RoughSets (version 1.0-0)

FS.reduct.computation: The reduct computation methods based on RST and FRST

Description

It is an additional function aimed as wrapper of approaches calculating a reduct.

Usage

FS.reduct.computation(decision.table,
    method = "greedy.heuristic", ...)

Arguments

decision.table

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

method

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

...

other parameters. See the parameters on FS.greedy.heuristic.reduct.RST,

FS.nearOpt.fvprs.FRST and

Value

• A class "FeatureSubset". See FS.greedy.heuristic.reduct.RST

  or FS.nearOpt.fvprs.FRST.

Details

There exist three methods considered in this function based on RST and FRST as follows:

• "greedy.heuristic": it is the greedy heuristic method based on RST.

  SeeFS.greedy.heuristic.reduct.RST.

• "nearOpt.fvprs": it is the near-optimal reduction algorithm based on FRST.

  SeeFS.nearOpt.fvprs.FRST.

• "permutation.heuristic": it is the permutation heuristic approach based on RST.

  SeeFS.permutation.heuristic.reduct.RST.

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

See Also

D.discretization.RST, BC.LU.approximation.RST

Examples

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

## generate single reduct using RST
reduct.1 <- FS.reduct.computation(decision.table, method = "permutation.heuristic")

## generate single reduct using FRST
reduct.2 <- FS.reduct.computation(decision.table, method = "nearOpt.fvprs")

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

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