[jira] [Commented] (FLINK-7631) Ineffective check in PageRank#open()

2017-10-03 Thread Greg Hogan (JIRA) 

[ 
https://issues.apache.org/jira/browse/FLINK-7631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16189835#comment-16189835
 ] 

Greg Hogan commented on FLINK-7631:
---

When `vertexCount` is zero the map function will not be called.

> Ineffective check in PageRank#open()
> 
>
> Key: FLINK-7631
> URL: https://issues.apache.org/jira/browse/FLINK-7631
> Project: Flink
>  Issue Type: Bug
>Reporter: Ted Yu
>Priority: Minor
>
> From 
> flink-libraries/flink-gelly/src/main/java/org/apache/flink/graph/library/linkanalysis/PageRank.java
>  :
> {code}
>   this.vertexCount = vertexCountIterator.hasNext() ? 
> vertexCountIterator.next().getValue() : 0;
>   this.uniformlyDistributedScore = ((1 - dampingFactor) + dampingFactor * 
> sumOfSinks) / this.vertexCount;
> {code}
> The check for vertexCountIterator.hasNext() should enclose the assignments to 
> both this.vertexCount and this.uniformlyDistributedScore
> Otherwise there may be divide by zero error.



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[jira] [Commented] (FLINK-7631) Ineffective check in PageRank#open()

2017-09-24 Thread Ted Yu (JIRA) 

[ 
https://issues.apache.org/jira/browse/FLINK-7631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16178375#comment-16178375
 ] 

Ted Yu commented on FLINK-7631:
---

Looking at rest of the class, the use of uniformlyDistributedScore doesn't seem 
to handle {{Infinity}}

> Ineffective check in PageRank#open()
> 
>
> Key: FLINK-7631
> URL: https://issues.apache.org/jira/browse/FLINK-7631
> Project: Flink
>  Issue Type: Bug
>Reporter: Ted Yu
>Priority: Minor
>
> From 
> flink-libraries/flink-gelly/src/main/java/org/apache/flink/graph/library/linkanalysis/PageRank.java
>  :
> {code}
>   this.vertexCount = vertexCountIterator.hasNext() ? 
> vertexCountIterator.next().getValue() : 0;
>   this.uniformlyDistributedScore = ((1 - dampingFactor) + dampingFactor * 
> sumOfSinks) / this.vertexCount;
> {code}
> The check for vertexCountIterator.hasNext() should enclose the assignments to 
> both this.vertexCount and this.uniformlyDistributedScore
> Otherwise there may be divide by zero error.



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[jira] [Commented] (FLINK-7631) Ineffective check in PageRank#open()

2017-09-18 Thread Greg Hogan (JIRA) 

[ 
https://issues.apache.org/jira/browse/FLINK-7631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16169958#comment-16169958
 ] 

Greg Hogan commented on FLINK-7631:
---

Divide by zero is only an error for fixed-point arithmetic and here the 
numerator is a double.

> Ineffective check in PageRank#open()
> 
>
> Key: FLINK-7631
> URL: https://issues.apache.org/jira/browse/FLINK-7631
> Project: Flink
>  Issue Type: Bug
>Reporter: Ted Yu
>Priority: Minor
>
> From 
> flink-libraries/flink-gelly/src/main/java/org/apache/flink/graph/library/linkanalysis/PageRank.java
>  :
> {code}
>   this.vertexCount = vertexCountIterator.hasNext() ? 
> vertexCountIterator.next().getValue() : 0;
>   this.uniformlyDistributedScore = ((1 - dampingFactor) + dampingFactor * 
> sumOfSinks) / this.vertexCount;
> {code}
> The check for vertexCountIterator.hasNext() should enclose the assignments to 
> both this.vertexCount and this.uniformlyDistributedScore
> Otherwise there may be divide by zero error.



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