igraph 的联合功能问题

Question

我尝试在 2 个图上使用 union 函数，其中引入了同一图 G 的子图（因此它们之间没有冲突）。我的问题是原始图（和子图）是加权的，另一方面这些子图的并集不是。

这是我创建子图的代码（权重可以采用 {1, 2, 3, 4, 5} 中的值：

weights <- E(g)$weight
graphs <- list()
for (r in seq(5)) {
  graphs[[r]] <- delete.edges(g, E(g)[weights!=r])
}
 
reduced_graphs <- list()
x <- numeric(5)
y <- numeric(5)
for (r in seq(5)) {
  reduced_graphs[[r]] <- delete.vertices(graphs[[r]], V(graphs[[r]])[degree(graphs[[r]])<=-1])
  
  y[r] <- length(get_users(reduced_graphs[[r]]))
  
  reduced_graphs[[r]] <- induced_subgraph(reduced_graphs[[r]], c(sample(get_users(reduced_graphs[[r]]), y[r]^sqrt(4.3/10)), get_movies(reduced_graphs[[r]])))
    
  x[r] <- length(get_movies(reduced_graphs[[r]]))
  
  reduced_graphs[[r]] <- induced_subgraph(reduced_graphs[[r]], c(sample(get_movies(reduced_graphs[[r]]), x[r]^(4.3/10)), get_users(reduced_graphs[[r]])))
  
  reduced_graphs[[r]] <- delete.vertices(reduced_graphs[[r]],  V(reduced_graphs[[r]])[degree(reduced_graphs[[r]])==0])
}

这是给我带来问题的代码：

reduced_graph <- igraph::union(reduced_graphs[[1]], reduced_graphs[[2]])
is_weighted(reduced_graph)
[1] FALSE
is_weighted(reduced_graphs[[1]])
[1] TRUE
is_weighted(reduced_graphs[[2]])
[1] TRUE

事实证明，生成的图形的顶点也丢失了它们的其他属性（如类型和颜色）：

V(reduced_graph)$type
NULL
V(reduced_graph)$color
NULL

有谁知道如何解决这个问题？谢谢！

OS: Windows 10 亲工作室 igraph 版本：1.2.6

Answer 1

也许您可以尝试以下解决方法

graph_from_data_frame(
  unique(
    do.call(
      rbind,
      lapply(reduced_graphs, get.data.frame)
    )
  )
)

igraph 的联合功能问题

Issue with union function of igraph

r

graph-theory

igraph

subgraph