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https://issues.apache.org/jira/browse/GEARPUMP-349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16166185#comment-16166185
]
ASF GitHub Bot commented on GEARPUMP-349:
-----------------------------------------
Github user huafengw commented on a diff in the pull request:
https://github.com/apache/incubator-gearpump/pull/223#discussion_r138880775
--- Diff: core/src/main/scala/org/apache/gearpump/util/Graph.scala ---
@@ -81,28 +86,35 @@ class Graph[N, E](vertexList: List[N], edgeList:
List[(N, E, N)]) extends Serial
* out degree
*/
def outDegreeOf(node: N): Int = {
- edges.count(_._1 == node)
+ outgoingEdgesOf(node).size
}
/**
* in degree
*/
def inDegreeOf(node: N): Int = {
- edges.count(_._3 == node)
+ incomingEdgesOf(node).size
}
/**
* out going edges.
*/
def outgoingEdgesOf(node: N): List[(N, E, N)] = {
- edges.filter(_._1 == node)
+ _outEdges.getOrElse(node, List.empty)
}
/**
* incoming edges.
*/
def incomingEdgesOf(node: N): List[(N, E, N)] = {
- edges.filter(_._3 == node)
+ _inEdges.getOrElse(node, List.empty)
+ }
+
+ /**
+ * adjacent vertices.
+ */
+ def adjacentVertices(node: N): List[N] = {
--- End diff --
It's a directed graph
> 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
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