R/ALG_average.R

In ludovikcoba/rrecsys: Environment for Evaluating Recommender Systems

#Algorithm that generates predictions based on the global average only.


globalAverage <- function(data) {
    
    average <- averageRating(data)
    
    average <- matrix(1, 
                      nrow = nrow(data), 
                      ncol = ncol(data)) * average
    
    new("algAverageClass", 
        alg = "globalAverage", 
        data = data, 
        average = average)
    
}

#Algorithm that generates predictions based on the items average only.
itemAverage <- function(data) {
  
  
  
    average <- colAverages(data)

    names(average) <- NULL
    
    if (any(is.nan(average))) {
        average[which(is.nan(average))] <- sum(data@data) / numRatings(data)
    }
    
    average <- matrix(rep(average, nrow(data)), 
                      nrow = nrow(data), 
                      byrow = TRUE)
    
    new("algAverageClass", 
        alg = "itemlAverage", 
        data = data, 
        average = average)
    
}

#Algorithm that generates predictions based on the user average only.
userAverage <- function(data) {
    
    average <- rowAverages(data)
    
    names(average) <- NULL
    
    if (any(is.nan(average))) {
        average[which(is.nan(average))] <- sum(data@data) / numRatings(data)
    }
    
    average <- matrix(rep(average, ncol(data)), 
                      nrow = nrow(data), 
                      byrow = F)
    
    new("algAverageClass", 
        alg = "userAverage", 
        data = data, 
        average = average)
    
}

rrecsysRegistry$set_entry(alg = "itemAverage", 
                          fun = itemAverage, 
                          description = "Item average",
                          reference = NA,
                          parameters = NA)

rrecsysRegistry$set_entry(alg = "userAverage", 
                          fun = userAverage, 
                          description = "User average",
                          reference = NA,
                          parameters = NA)

rrecsysRegistry$set_entry(alg = "globalAverage", 
                          fun = globalAverage, 
                          description = "Global average", 
                          reference = NA,
                          parameters = NA)