R "HybridRecommender" in recommenderlab package unable to predict "binaryRatingMatrix"

Question

I'm trying to apply "HybridRecommender" on "binaryRatingMatrix" type data, but i got an error when trying to predict "topNList".

I'm current running R-64bit (version 3.4.4) on windows machine with recommenderlab version 0.2-2

Below is the sample dataset

m <- matrix(sample(c(0,1), 50, replace=TRUE), nrow=5, ncol=10,
            dimnames=list(users=paste("u", 1:5, sep=''),
                           items=paste("i", 1:10, sep='')))

Convert matrix into binaryRatingMatrix

b <- as(m, "binaryRatingMatrix")

Compute HybridRecommender

system.time(
     recom <- recommenderlab::HybridRecommender(
         Recommender(b, method = "AR"),
         Recommender(b, method = "IBCF"),
         Recommender(b, method = "POPULAR"),
         Recommender(b, method = "UBCF"),
         weights = c(.25, .25, .25, .25))
)

Compute predicted recommendation items "topNList" (with error)

as(predict(recom, 1, newdata = b, type = "topNList", n = 10), "list")

Error in match.arg(type) : 'arg' should be one of “topNList”

My expected results would be the same as below, i tried to run on single recommender and it works well

r <- Recommender(b, method = "AR")
as(predict(r, 1, newdata = b, type = "topNList", n = 10), "list")

$u1
character(0)

$u2
[1] "i10" "i2"  "i5"  "i6"  "i9"  "i8" 

$u3
[1] "i4" "i6" "i9" "i8" "i3"

$u4
[1] "i9" "i8"

$u5
[1] "i7"  "i3"  "i2"  "i10" "i4"  "i5"  "i6"  "i1"

New Edit: Tried "HybridRecommender" on "realRatingMatrix", it work as normal

data(Jester5k)

class(Jester5k)
[1] "realRatingMatrix"
attr(,"package")
[1] "recommenderlab"

system.time(
  recom <- HybridRecommender(
      Recommender(Jester5k, method = "POPULAR"),
      Recommender(Jester5k, method = "IBCF"),
      Recommender(Jester5k, method = "SVDF"),
      Recommender(Jester5k, method = "UBCF"),
      weights = c(.25, .25, .25, .25))
)

getList(predict(recom, 1:5, Jester5k, n = 5))

[[1]]
[1] "j84" "j85" "j83" "j82" "j81"

[[2]]
[1] "j89" "j93" "j76" "j81" "j88"

[[3]]
character(0)

[[4]]
character(0)

[[5]]
[1] "j80"  "j81"  "j100" "j72"  "j89" 

Question: I'm curious to know why the predict unable to work on "HybridRecommender" while it works on single "Recommender" and "realRatingMatrix"? Any comment and help are appreciated. Thanks!

Answer 1

Is a bug and the issue solved on latest development version (version 0.2-4.1), current available on Github. Kindly check the details Here