Spark GraphX例子

Spark GraphX例子

假定我們想從一些文本文件中構(gòu)建一個圖，限制這個圖包含重要的關(guān)系和用戶，并且在子圖上運行page-rank，最后返回與top用戶相關(guān)的屬性。可以通過如下方式實現(xiàn)。

// Connect to the Spark cluster
val sc = new SparkContext("spark://master.amplab.org", "research")

// Load my user data and parse into tuples of user id and attribute list
val users = (sc.textFile("graphx/data/users.txt")
  .map(line => line.split(",")).map( parts => (parts.head.toLong, parts.tail) ))

// Parse the edge data which is already in userId -> userId format
val followerGraph = GraphLoader.edgeListFile(sc, "graphx/data/followers.txt")

// Attach the user attributes
val graph = followerGraph.outerJoinVertices(users) {
  case (uid, deg, Some(attrList)) => attrList
  // Some users may not have attributes so we set them as empty
  case (uid, deg, None) => Array.empty[String]
}

// Restrict the graph to users with usernames and names
val subgraph = graph.subgraph(vpred = (vid, attr) => attr.size == 2)

// Compute the PageRank
val pagerankGraph = subgraph.pageRank(0.001)

// Get the attributes of the top pagerank users
val userInfoWithPageRank = subgraph.outerJoinVertices(pagerankGraph.vertices) {
  case (uid, attrList, Some(pr)) => (pr, attrList.toList)
  case (uid, attrList, None) => (0.0, attrList.toList)
}

println(userInfoWithPageRank.vertices.top(5)(Ordering.by(_._2._1)).mkString("\n"))