CODEWITHSUNDEEP
rmatrixmachine-learningsparse-matrixrecommendation-engine
Nelson
Nelson

Reputation: 301

Convert sparse matrix (dgCMatrix) to realRatingMatrix

I've converted a data frame to a sparse matrix to avoid memory issues and save space, once the original data doesn't fit in the memory.

Now, I need to convert this sparse matrix to a realratingmatrix so I can build a recommender with recommenderlab, but i got the following error:

Error in as(aux_max, "realRatingMatrix") : 
  no method or default for coercing “dgCMatrix” to “realRatingMatrix”

My sample code is the following:

library(Matrix)
UserID<-c(10090,10090,10090,10316,10316)
MovieID <-c(63155,63530,63544,63155,63545)
Rating <-c(2,2,1,2,1)
trainingData<-data.frame(UserIDa,MovieID,Rating)

UIMatrix <- sparseMatrix(i = as.integer(as.factor(trainingData$UserID)),
                         j = as.integer(as.factor(trainingData$MovieID)),
                         x = trainingData$Rating
                        )

dimnames(UIMatrix) <- list(sort(unique(trainingData$UserID)),
                           sort(unique(trainingData$MovieID)))

rrm <- as(UIMatrix, "realRatingMatrix")

Can anyone give some advise on how to solve that?

Upvotes: 2

Views: 5590

Answers (2)

Scott
Scott

Reputation: 11

I just received this error (no method or default for coercing “matrix” to “realRatingMatrix”), I needed to install library(recommenderlab) package.

error message and solution

Upvotes: 1

Nelson
Nelson

Reputation: 301

Well, I think I got the answer. I coerced the "dgCMatrix" to "matrix" and then to "realratingmatrix". Seems to work fine.

rrm<- as(  as(UIMatrix, "matrix")   , "realRatingMatrix")

Upvotes: 3

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