bug in MovieLens indices

[CarloLucibello]

Something is odd with the MovieLens dataset:

julia> d = MovieLens("100k")[1]
Heterogeneous Graph:
  node_types    =>    2-element Vector{String}
  edge_types    =>    1-element Vector{Tuple{String, String, String}}
  num_nodes     =>    Dict{String, Int64} with 2 entries
  num_edges     =>    Dict{Tuple{String, String, String}, Int64} with 1 entry
  edge_indices  =>    Dict{Tuple{String, String, String}, Tuple{Vector{Int64}, Vector{Int64}}} with 1 entry
  node_data     =>    Dict{String, Dict} with 2 entries
  edge_data     =>    Dict{Tuple{String, String, String}, Dict} with 1 entry

julia> d.num_nodes
Dict{String, Int64} with 2 entries:
  "movie" => 1682
  "user"  => 943

julia> d.num_edges   # THIS SHOULD BE 100k
Dict{Tuple{String, String, String}, Int64} with 1 entry:
  ("user", "rating", "movie") => 200000

julia> d.edge_indices[("user", "rating", "movie")][1] |> maximum # THIS SHOULD BE 943
1682

I suspect reverse edges are added, which is wrong since the relation goes in one direction. Is this the case @Dsantra92?

[Dsantra92]

Now that I look at it, the rating edge should be uni-directional. I will open a pr for this shortly.