1解释

简单不详述


2.代码：

/**
 * @author xubo
 * ref http://spark.apache.org/docs/1.5.2/graphx-programming-guide.html
 * time 20160503
 */

package org.apache.spark.graphx.learning

import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.graphx.Graph
import org.apache.spark.graphx.VertexRDD
import org.apache.spark.graphx.util.GraphGenerators

object GraphGeneratorsAndIndegreeOutdegree {

  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setAppName("GraphOperatorsStructuralMask").setMaster("local[4]")
    // Assume the SparkContext has already been constructed
    val sc = new SparkContext(conf)

    // Import random graph generation library
    // Create a graph with "age" as the vertex property.  Here we use a random graph for simplicity.
    val graph: Graph[Double, Int] =
      GraphGenerators.logNormalGraph(sc, numVertices = 5).mapVertices((id, _) => id.toDouble)
    // Compute the number of older followers and their total age

      println("Graph:");
    println("sc.defaultParallelism:" + sc.defaultParallelism);
    println("vertices:");
    graph.vertices.collect.foreach(println(_))
    println("edges:");
    graph.edges.collect.foreach(println(_))
    println("count:" + graph.edges.count);
    println("\ninDegrees");
    graph.inDegrees.foreach(println)
    println("\noutDegrees");
    graph.outDegrees.foreach(println)
    println("\nreverse");
    println("\nreverse vertices");
    graph.reverse.vertices.collect.foreach(println)
    println("\nreverse edges");
    graph.reverse.edges.collect.foreach(println)
    println("\nreverse inDegrees");
    graph.reverse.inDegrees.foreach(println)
     println("\nreverse inDegrees");
    graph.reverse.outDegrees.foreach(println)
  }

}


reverse主要是将边的方向反向


3.结果：

Graph:
sc.defaultParallelism:4
vertices:
(4,4.0)
(0,0.0)
(1,1.0)
(2,2.0)
(3,3.0)
edges:
Edge(0,0,1)
Edge(0,2,1)
Edge(0,2,1)
Edge(0,3,1)
Edge(1,3,1)
Edge(1,4,1)
Edge(1,4,1)
Edge(1,4,1)
Edge(2,0,1)
Edge(2,3,1)
Edge(2,3,1)
Edge(2,4,1)
Edge(3,1,1)
Edge(3,3,1)
Edge(4,0,1)
Edge(4,1,1)
Edge(4,2,1)
Edge(4,4,1)
count:18

inDegrees
(3,5)
(1,2)
(4,5)
(0,3)
(2,3)

outDegrees
(2,4)
(3,2)
(1,4)
(4,4)
(0,4)

reverse

reverse vertices
(4,4.0)
(0,0.0)
(1,1.0)
(2,2.0)
(3,3.0)

reverse edges
Edge(0,0,1)
Edge(2,0,1)
Edge(2,0,1)
Edge(3,0,1)
Edge(3,1,1)
Edge(4,1,1)
Edge(4,1,1)
Edge(4,1,1)
Edge(0,2,1)
Edge(3,2,1)
Edge(3,2,1)
Edge(4,2,1)
Edge(0,4,1)
Edge(1,3,1)
Edge(1,4,1)
Edge(2,4,1)
Edge(3,3,1)
Edge(4,4,1)

reverse inDegrees
(4,4)
(0,4)
(2,4)
(1,4)
(3,2)

reverse inDegrees
(2,3)
(1,2)
(3,5)
(4,5)
(0,3)




参考

【1】 http://spark.apache.org/docs/1.5.2/graphx-programming-guide.html