isSubset.R

isSubset.R

library(foreach)
library(doParallel)
library(arules)
library(Rcpp)
library(isSub)  #this is our Rcpp library

#register cores
registerDoParallel(3)  

#function searching for a subsets
issub=function(data){
  
  issub=rep(0,nrow(data))
  Antecedent=data$lhs
  Consequent=data$rhs
  length=nrow(data)
  
  for(i in 1:length){
    for(j in (i+1):length){
      if(isTRUE(grepl(Antecedent[j], Antecedent[i]))){
        issub[i]=1
      }  
      else if(isTRUE(grepl(Antecedent[i], Antecedent[j]))){
        
        issub[j]=1
      }  
      
    }
  }
  data$isSubset=issub
  return(data)
}

#change datatype of rhs and lhs to character, removing '{}'

data$lhs=as.character(data$lhs)
data$rhs=as.character(data$rhs)
data$lhs=gsub('[{}]',replace='',data$lhs)
data$rhs=gsub('[{}]',replace='',data$rhs)

#create table of unique consequents-used for parallel computation with foreach
listOfUniqueConsequents=table(data$rhs)


#here calculation are performed sequentially, after division of the dataset into subgroups of unique consequents
resultsSequentiallyR=c()
resultsSequentiallyRcpp=c()
for(i in 1:length(listOfUniqueConsequents)){
  subset=data[which(data$rhs==as.character(as.integer(names(listOfUniqueConsequents[i])))),] 
  resultsSequentiallyR=c(resultsSequentiallyR,issub(subset))
  resultsSequentiallyRcpp=c(resultsSequentiallyRcpp,isSubset(subset))
}



#foreach with Rcpp function-remember to include package, otherwise function would not be exported
resultsParallelRcpp=foreach(k=1:length(listOfUniqueConsequents),.packages=c("isSub"))%dopar%{isSubset(data[which(data$rhs==as.character(as.integer(names(listOfUniqueConsequents[k])))),])}

#foreach with R function
resultsParallelR=foreach(k=1:length(listOfUniqueConsequents))%dopar%{issub(data[which(data$rhs==as.character(as.integer(names(listOfUniqueConsequents[k])))),])}