Hi Greg,
I do an evaluation between Gelly and GraphX (Spark). Both frameworks implement
PageRank and Gelly provides a lot of variants (*thumbs up*).
During a really small initial test I get for the vertex-centric, scatter-gather
and gsa version the same ranking result. Just the implementation in 1.3.X
(without any graph model) computed a different result (ranking).
/* vertex centric */
DataSet<Vertex<Double, Double>> pagerankVC = small.run(new PageRank<>(0.5, 10));
System.err.println("VC");
pagerankVC.printToErr();
/* scatter gather */
DataSet<Vertex<Double, Double>> pageRankSG = small
.run(new org.apache.flink.graph.library.PageRank<>(0.5, 10));
System.err.println("SG");
pageRankSG.printToErr();
/* gsa */
DataSet<Vertex<Double, Double>> pageRankGSA = small.run(new GSAPageRank<>(0.5,
10));
System.err.println("GSA");
pageRankGSA.printToErr();
/* without graph model */
DataSet<Result<Double>> pageRankDI = small
.run(new PageRank<>(0.5, 10));
System.err.println("delta iteration");
pageRankDI.printToErr();
My input graph is:
vertices
* id 1, val 0
* id 2, val 0
* id 3, val 0
* id 4, val 0
edges
* src 1, trg 2, val 3
* src 1, trg 1, val 2
* src 2, trg 1, val 3
* src 2, trg 4, val 6
Ranking output
* vertex-centric
* id 4 with 1.16
* id 1 with 1.103
* id 2 with 0.815
* id 3 with 0
* sg and gsa
* id 4 with 2.208
* id 1 with 2.114
* id 2 with 1.546
* id 3 with 0
* new PageRank in Gelly 1.3.X
* id 1 with 0.392
* id 2 with 0.313
* id 4 with 0.294
Do you know why?
Best
Marc
Am 23.07.2017 um 02:22 schrieb Greg Hogan
<c...@greghogan.com<mailto:c...@greghogan.com>>:
Hi Marc,
PageRank and GSAPageRank were moved to the flink-gelly-examples jar in the
org.apache.flink.graph.examples package. A library algorithm was added that
supports both source and sink vertices. This limitation of the old algorithms
was noted in the class documentation and I understand to be an effect of delta
iterations. The new implementation is also significantly faster
(https://github.com/apache/flink/pull/2733#issuecomment-278789830).
PageRank can be run using the examples jar from the command line, for example
(don’t wildcard the jar file as in the documentation until we get the javadoc
jar removed from the next release).
$ mv opt/flink-gelly* lib/
$ ./bin/flink run examples/gelly/flink-gelly-examples_2.11-1.3.1.jar \
--algorithm PageRank \
--input CSV --type integer --simplify directed --input_filename <filename>
--input_field_delimiter $'\t' \
--output print
The output can also be written to CSV in similar fashion to the input.
The code to call the library PageRank from the examples driver is as with any
GraphAlgorithm
(https://github.com/apache/flink/blob/release-1.3/flink-libraries/flink-gelly-examples/src/main/java/org/apache/flink/graph/drivers/PageRank.java):
graph.run(new PageRank<K, VV, EV>(dampingFactor, iterations,
convergenceThreshold));
Please let us know of any issues or additional questions!
Greg
On Jul 22, 2017, at 4:33 PM, Kaepke, Marc
<marc.kae...@haw-hamburg.de<mailto:marc.kae...@haw-hamburg.de>> wrote:
Hi there,
why was the PageRank version (which implements the GraphAlgorithm interface)
removed in 1.3?
How can I use the new PageRank implementation in 1.3.x?
Why PageRank doesn’t use the graph processing models (vertex-centric, sg or
gsa) anymore?
Thanks!
Bests,
marc
