I'm running igraph to do some experiments, and for some graphs I notice the number of vertices in the analysis output table (e.g. the output of evcent (graph, directed = FALSE)) is less than the vertices used as input (edge list).
Because this only happens for some typical graphs (quite disconnected), I'm assuming this occurs because there is no weight assigned to this vertice (i.e. value zero). Is this true? Or is something else going wrong here?
Many thanks,