[ 
https://issues.apache.org/jira/browse/GEARPUMP-349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16167223#comment-16167223
 ] 

ASF GitHub Bot commented on GEARPUMP-349:
-----------------------------------------

Github user manuzhang commented on a diff in the pull request:

    https://github.com/apache/incubator-gearpump/pull/223#discussion_r139049560
  
    --- Diff: core/src/main/scala/org/apache/gearpump/util/Graph.scala ---
    @@ -156,64 +155,64 @@ class Graph[N, E](vertexList: List[N], edgeList: 
List[(N, E, N)]) extends Serial
        * Current Graph is not changed.
        */
       def mapVertex[NewNode](fun: N => NewNode): Graph[NewNode, E] = {
    -    val vertexes = vertices.map(node => (node, fun(node)))
    +    val newVertexes = getVertices.map(node => (node, fun(node)))
     
    -    val vertexMap: Map[N, NewNode] = vertexes.toMap
    +    val vertexMap: Map[N, NewNode] = newVertexes.toMap
     
    -    val newEdges = edges.map { edge =>
    +    val newEdges = getEdges.map { edge =>
           (vertexMap(edge._1), edge._2, vertexMap(edge._3))
         }
    -    new Graph(vertexes.map(_._2), newEdges)
    +    new Graph(newVertexes.map(_._2), newEdges)
    --- End diff --
    
    I believe the plural of Vertex is Vertices


> Graph#topologicalOrderIterator is slow for large graph
> ------------------------------------------------------
>
>                 Key: GEARPUMP-349
>                 URL: https://issues.apache.org/jira/browse/GEARPUMP-349
>             Project: Apache Gearpump
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 0.8.4
>            Reporter: Manu Zhang
>            Assignee: Huafeng Wang
>             Fix For: 0.8.5
>
>
> The algorithm is as follows
> 1. find zero in-degree nodes from a copied graph. 
> 2. remove nodes from the copied graph and add them to the output
> 3. repeat 1
> The issue is that step 1 traverses all remaining nodes each time, which costs 
> the algorithm {{O(n^2)}} time
> {{Graph#hasCycle}} has a similar issue



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Reply via email to