[
https://issues.apache.org/jira/browse/FLINK-3772?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15245760#comment-15245760
]
Greg Hogan commented on FLINK-3772:
-----------------------------------
Each of the "join" methods is implemented as a {{coGroup}} as is each of the
degree methods, so the trade-off is a {{coGroup}} vs a {{reduce}} to calculate
each degree, and a {{coGroup}} vs a hash-join for each annotated degree. As you
note the user is required to compose multiple methods and must be aware of
implementation details such as using {{inDegrees}} or {{outDegrees}} instead of
{{getDegrees}} on an undirected graph. Performance impacts include the use of
{{coGroup}}, immutable types, and that the degree functions materialize the
vertex set.
I see these {{GraphAlgorithm}} as providing a different set of capabilities
from the {{Graph}} API, as demonstrated in the {{ClusteringCoefficient}} PR. I
think Flink benefits from having optimized algorithms as composable building
blocks for more complex algorithms.
> Graph algorithms for vertex and edge degree
> -------------------------------------------
>
> Key: FLINK-3772
> URL: https://issues.apache.org/jira/browse/FLINK-3772
> Project: Flink
> Issue Type: New Feature
> Components: Gelly
> Affects Versions: 1.1.0
> Reporter: Greg Hogan
> Assignee: Greg Hogan
> Fix For: 1.1.0
>
>
> Many graph algorithms require vertices or edges to be marked with the degree.
> This ticket provides algorithms for annotating
> * vertex degree for undirected graphs
> * vertex out-, in-, and out- and in-degree for directed graphs
> * edge source, target, and source and target degree for undirected graphs
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
