R：网络分析 - 操纵邻接矩阵以获得“公共链接”矩阵

1 回答

• 0

  有趣但有点模糊定义的问题 . 我在理解你想要的输出时遇到了一些麻烦，但我想我明白了 . 我在下面的第一次尝试中留下了代码 . 您提供的示例数据我称之为 g .

  无论哪种方式，我认为你可以从这个代码示例中继续下去 . 我非常愿意以更聪明的方式做到这一点而没有速度循环，但这是我能想到的最教学的代码，因为我不确定所需的输出 .

  如果我正确理解你的问题，你要求的内容将在列表ul中输出 ul[[x]][[3]] 包含图表的E（），其中边缘从节点i（ ul[[x]][[1]] ）到i和j共享传入的每个节点图表中的链接 g .

  library(igraph)
  
  # Assume 4 nodes:
  # - node A is connected to node C,
  # - node B is connected to A,
  # - node C is connected to node A and B,
  # - node D connected to A
  m <- matrix(ncol=4,c(0,0,1,0,
              1,0,0,0,
              1,1,0,0,
              1,0,0,0), byrow=T)
  colnames(m) <- rownames(m) <-  c("A","B","C","D")
  
  # Uncomment this stuff to use random network instead
  # g <- erdos.renyi.game(n=12, 16, type="gnm", directed=TRUE, loops=FALSE)
  # m <- as.matrix(as_adjacency_matrix(g))
  
  # Check that the data is ok
  graph_from_adjacency_matrix(m, mode="directed")
  g <- graph_from_adjacency_matrix(m, mode="directed")
  
  # Directed weighted adjacency list from the original one, where
  # each entry [i,j] represents the sum of the value of incoming
  # edge that node i,j share with each other.
  
  
  # I first missunderstood your question and wrote this output
  
  # This output will be an edgelist containing node-pairs i and j and
  # the strength related to the number of other nodes whith which they
  # share incoming links.
  el <- matrix(ncol=3, nrow=0)
  colnames(el) <- c("i","j","strength")
  
  # I then reread your question and made this output containing a list
  # wehre every node-pair which share incoming links from the same nodes
  # contain the E()-object of igraph-edges from i to each of the nodes
  # from which both i and j recieve incoming links in the graph g.
  ul <- list()
  
  # Use the empty graph like g to build edgelists
  temp.g <- g %>% delete_edges(E(g)) # an empty graph
  
  for(i in V(g)){
      for(j in V(g)){
          # Each node pair is i j for every node in g
          if(i == j){next}
  
  
          # Neighborhod() lists linked nodes, in this case at the distance
          # of exactly 1 (mindist and order) for node x using the "in"-coming
          # links:
          in.to.i <- neighborhood(g, order=1, nodes=i, mode="in", mindist=1)
          in.to.j <- neighborhood(g, order=1, nodes=j, mode="in", mindist=1)
  
          # These are the nodes which all link to both i and j
          shared.incoming <- intersect(in.to.i[[1]], in.to.j[[1]])
  
          # Make a new graph (gg) with links from each node FROM which i and j both
          # share incoming ties in g TO  i.
          # In the edgelist ul, each row can be read like:
          # In graph g, "i" has "edges" incoming ties in common with "j"
          gg <- temp.g %>% add_edges(unlist(lapply(shared.incoming, function(x) c(x,i)) ))
  
          # E(gg) is what you want. Add it to the output-list
          ul[[length(ul)+1]] <- list(i, j, as_edgelist(gg, names=T))
  
          # how many nodes link to both i and j?
          el <- rbind(el,c("i"=i, "j"=j, "edges"=length(shared.incoming) ) )
      }
  }
  
  # The whole list of el contains all possible pairs
  el
  
  # Strip entries in the edgelist where a pair of nodes don't share any
  # in-linking nodes at all
  el <- el[el[,'strength'] != 0,  ]
  
  # Since nodes that share in-linking nodes are ALWAYS structually equivilent
  # in that they both share in-links from the same other nodes, there is never
  # any idea to have this edge-list directed.
  # Make the edge-list one-directed by deleting duplicate pairs
  el <- el[el[,'i'] < el[,'j'],  ]
  
  # In graph g, these node-pairs share the number of [strength] incoming links
  # from the same other nodes.
  (el)
  
  
  # The whole list of ul contains all possible pairs
  ul
  
  # You only wanted the pairs which actually contained any shared incoming nodes
  keep.from.ul <- unlist(lapply(ul, function(x) ifelse( nrow(x[[3]]) > 0, TRUE, FALSE) ))
  ul <- ul[keep.from.ul]
  

  回复于 2024-05-04T11:19:54+08:00