Question

我在这里有点困惑，我使用以下代码提取了断开连接图的巨型组件。

function(graph) {
  cl <- clusters(graph)
  induced.subgraph(graph, which(cl$membership == which.max(cl$csize)))
}

但是在RStudio中运行这样的代码会给我带来常见错误，例如

is_connected(ngo.giant)
[1] TRUE
centr_clo(ngo.giant)$centralization
[1] 0.003214897
Warning message:
In centr_clo(ngo.giant) :
  At centrality.c:2784 :closeness centrality is not well-defined for disconnected graphs
temp<-centr_eigen(ngo.giant,directed=T)
Warning message:
In centr_eigen(ngo.giant, directed = T) :
  At centrality.c:344 :graph is directed and acyclic; eigenvector centralities will be zeros

是否有发生这种情况的原因？抱歉，如果该代码太含糊

Answer 1

我刚刚收到警告，我注意到这是由于我的图形是有向的，因此某些路径只能沿一个方向行走，而某些节点却与另一个节点“分离”。

test <- data.frame(source=c('a', 'a'), target=c('b', 'c'), stringsAsFactors=FALSE)
g <- igraph::graph_from_data_frame(test, directed=TRUE)
igraph::closeness(g)

        a         b         c 
0.5000000 0.1666667 0.1666667 
Warning message:
In igraph::closeness(g) :
  At centrality.c:2784 :closeness centrality is not well-defined for disconnected graphs

同样，如果您在mehtod='all'中使用参数closeness，则您的图形将被视为无向图。

警告消息：断开连接的图形的巨大组成部分本身已经断开

1 个答案: