incidence.md
In igraph: Network Analysis and Visualization

graph_from_biadjacency_matrix() works -- dense

Code
  (g <- graph_from_biadjacency_matrix(inc))
Output
  IGRAPH UN-B 8 7 -- 
  + attr: type (v/l), name (v/c)
  + edges (vertex names):
  [1] A--c A--d B--b B--c B--e C--b C--d

Code
  (weighted_g <- graph_from_biadjacency_matrix(inc, weighted = TRUE))
Output
  IGRAPH UNWB 8 7 -- 
  + attr: type (v/l), name (v/c), weight (e/n)
  + edges (vertex names):
  [1] A--c A--d B--b B--c B--e C--b C--d

graph_from_biadjacency_matrix() works -- dense + multiple

Code
  (g <- graph_from_biadjacency_matrix(inc, multiple = TRUE))
Output
  IGRAPH UN-B 8 10 -- 
  + attr: type (v/l), name (v/c)
  + edges (vertex names):
   [1] A--c A--d A--d A--e B--b B--e C--b C--c C--c C--e

graph_from_biadjacency_matrix() works -- sparse

Code
  (g <- graph_from_biadjacency_matrix(inc))
Output
  IGRAPH UN-B 8 7 -- 
  + attr: type (v/l), name (v/c)
  + edges (vertex names):
  [1] B--b C--b A--c B--c A--d C--d B--e

Code
  (weighted_g <- graph_from_biadjacency_matrix(inc, weighted = TRUE))
Output
  IGRAPH UNWB 8 7 -- 
  + attr: type (v/l), name (v/c), weight (e/n)
  + edges (vertex names):
  [1] B--b C--b A--c B--c A--d C--d B--e

graph_from_biadjacency_matrix() works -- sparse + multiple

Code
  (g <- graph_from_biadjacency_matrix(inc, multiple = TRUE))
Output
  IGRAPH UN-B 8 10 -- 
  + attr: type (v/l), name (v/c)
  + edges (vertex names):
   [1] B--b C--b A--c C--c C--c A--d A--d A--e B--e C--e

graph_from_biadjacency_matrix() errors well

Code
  (g <- graph_from_biadjacency_matrix(inc, weight = FALSE))
Condition
  Error in `graph_from_biadjacency_matrix()`:
  ! `weighted` can't be `FALSE`.
  i See `?graph_from_biadjacency_matrix()`'s manual page.

Code
  (g <- graph_from_biadjacency_matrix(inc, weight = 42))
Condition
  Error in `graph_from_biadjacency_matrix()`:
  ! `weighted` can't be a number.
  i See `?graph_from_biadjacency_matrix()`'s manual page.

Code
  (g <- graph_from_biadjacency_matrix(inc, multiple = TRUE, weighted = TRUE))
Condition
  Error in `graph_from_biadjacency_matrix()`:
  ! `multiple` and `weighted` cannot be both `TRUE`.
  igraph either interprets numbers larger than 1 as weights or as multiplicities, but it cannot be both.