Use the path count metric to compute a meta-path based similarity score.
get_pc(
  x,
  y,
  paths_x,
  paths_y = NULL,
  reference_list = NULL,
  list_type = NULL,
  verbose = TRUE
)ID of the origin node.
ID of the destination node.
Paths from the origin node following the meta-path of interest as a data.table.
Paths from the destination node following the meta-path of interest as a data.table.
Either an edge list as a data.table which must contain the columns Origin,
Destination, OriginType, DestinationType, and EdgeType, or a neighbor reference object constructed
by get_neighbor_list().
If an edge list is provided, specify "edge". If a neighbor list is provided, specify "neighbor".
Should the intermediate calculations be printed to the console?
A list with two elements:
The name of the similarity metric (i.e., "Path Count").
The path count similarity score.
Himmelstein, D. S. & Baranzini, S. E. Heterogeneous Network Edge Prediction: A Data Integration Approach to Prioritize Disease-Associated Genes. PLOS Computational Biology 11, e1004259 (2015).
get_neighbor_list() for neighbor reference object construction.
Other similarity: 
get_dwpc(),
get_npc(),
get_pathsim()