Below is R script snippets that I put into R studio.
Assignments
Rabbit <- c(10, 7, 1, 2, NA, 1)
Cow <- c( 7, 10, NA, NA, NA, NA)
Dog <- c(NA, 1, 10, 10, NA, NA)
Pig <- c( 5, 6, 4, NA, 7, 3)
Chicken <- c( 7, 6, 2, NA, 10, NA)
Pinguin <- c( 2, 2, NA, 2, 2, 10)
Bear <- c( 2, NA, 8, 8, 2, 7)
Lion <- c(NA, NA, 9, 10, 2, NA)
Tiger <- c(NA, NA, 8, NA, NA, 5)
Antilope <- c( 6, 10, 1, 1, NA, NA)
Wolf <- c( 1, NA, NA, 8, NA, 3)
Sheep <- c(NA, 8, NA, NA, NA, 2)
Create Array
animals <- c(“Rabbit”,”Cow”,”Dog”,”Pig”,”Chicken”,”Pinguin”,”Bear”,”Lion”,”Tiger”,”Antilope”,”Wolf”,”Sheep”)
foods <- c(“Carrots”,”Grass”,”Pork”, “Beef”, “Corn”, “Fish”)
matrixRowAndColNames <- list(animals, foods)
Create Matrix
animal2foodRatings <-matrix(data=c(Rabbit,Cow,Dog,Pig,Chicken,Pinguin,Bear,Lion,Tiger,Antilope,Wolf,Sheep),nrow=12,ncol=6,byrow=TRUE,matrixRowAndColNames)
animal2foodRatingsWithMean <- animal2foodRatingsanimal2foodRatingsWithMean[is.na(animal2foodRatingsWithMean)] <- mean(rowMeans(animal2foodRatingsRecMatrix))
FactorStructure <- svd(animal2foodRatingsWithMean)
#
D <- diag(FactorStructure$d)
PredictedRatings <- FactorStructure$u %*% D %*% t(FactorStructure$v)
dimnames(PredictedRatings) <- matrixRowAndColNames
PredictiveMatrix <- matrix(nrow=length(animals), ncol=length(foods))
dimnames(PredictiveMatrix) <- matrixRowAndColNames
# Sheep Carrots prediction
k <- 2
for(animal in 1:length(animals)) {
for(food in 1:length(foods)) {
PredictiveMatrix[animal,food] <- (((FactorStructure$u[animal,1:k]*sqrt(FactorStructure$d[1:k]))%*%(sqrt(FactorStructure$d[1:k])*t(FactorStructure$v)[1:k,food]))[1,1])
}
}
PredictiveMatrix
library(recommenderlab)
animal2foodRatingsRecMatrix <- as(animal2foodRatings, “realRatingMatrix”)
animal2foodRatingsRecMatrix_n <- normalize(animal2foodRatingsRecMatrix)
animal2foodRatingsRecMatrix_n2 <- normalize(animal2foodRatingsRecMatrix, method=”Z-score”)
# Average user rating
mean(rowMeans(animal2foodRatingsRecMatrix))
# Average number of ratings per User
mean(rowCounts(animal2foodRatingsRecMatrix))
# Average number of ratings per Item
mean(colCounts(animal2foodRatingsRecMatrix))
# Amount of all ratings
length(getRatings(animal2foodRatingsRecMatrix))
# Histogram of ratings
hist(getRatings(animal2foodRatingsRecMatrix), breaks=10, main=paste(“Distribution of Ratings”))
image(animal2foodRatingsRecMatrix, main=”Raw Data”)
image(animal2foodRatingsRecMatrix_n, main=”Centered”)
image(animal2foodRatingsRecMatrix_n2, main=”Z-Score Normalization”)
rec <- Recommender(animal2foodRatingsRecMatrix[1:10,], method = “IBCF”)
recommenderRegistry$get_entry_names()
https://github.com/ManuelB/facebook-recommender-demo/blob/master/docs/BedConExamples.R
BigSnarf blog 