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From Oscar Henrichs Lucas Henrichs <oscar.henrichs.acade...@outlook.com>
Subject SAMOA - Issue with Naive Bayes and Boosting
Date Sun, 15 Mar 2020 23:43:34 GMT
Hi, I’m Oscar H. L. Henrichs,

I’m a student at Pontifícia Universidade Católica do Paraná - Brazil, and I’ve been
studying and implementing an study on Data Streams using Apache Samoa, under the supervision
of Jean Paul Barddal. Our initial goal is to test and validate the benefits of using Apache
Samoa, when comparing it with MOA and Spark.

So far we locally tested a few of the main learners of Apache Samoa, but we had some trouble
when using NaiveBayes, Boosting and AdaptiveBoosting. We are not sure if the issues raised
below have been solved in the new release, so we believe this is worthy of bringing up.

With NaïveBayes, we think the problem is the implementation of LocalLearner, as the LocalLearner
files seems incomplete or not extending the classes it should.

For instance, we are trying to run the following snippet, but it fails:

Comand:
$ bin/samoa local target/SAMOA-Local-0.5.0-incubating-SNAPSHOT.jar "PrequentialEvaluation
-l classifiers.NaiveBayes -s (ArffFileStream -f ARFFFfile/With_Change/SEA_wch_500k.arff) -f
100000"

Error:
"... Caused by: java.lang.Exception: Class named 'classifiers.NaiveBayes' is not an instance
of org.apache.samoa.learners.Learner ...".*It's just a cut of the full error log. I've annexed
the full log in the email.


As for the Boosting I believe that I do not know how to call it properly, as it seems as
it is really close to the Bagging process, but with a few extra steps that either it’s not
defined or not properly called.

This is the command we are trying to run, but again, it fails:

Comand:
$ bin/samoa local target/SAMOA-Local-0.5.0-incubating-SNAPSHOT.jar "PrequentialEvaluation
-l classifiers.NaiveBayes -s (ArffFileStream -f ARFFFfile/With_Change/SEA_wch_500k.arff) -f
100000"

Error:
"Successfully instantiating org.apache.samoa.tasks.PrequentialEvaluation
Exception in thread "main" java.lang.NullPointerException
at org.apache.samoa.learners.classifiers.ensemble.BaggingDistributorProcessor.process(BaggingDistributorProcessor.java:63)
at org.apache.samoa.topology.impl.SimpleProcessingItem.processEvent(SimpleProcessingItem.java:84)
at org.apache.samoa.topology.impl.SimpleStream.put(SimpleStream.java:72)
at org.apache.samoa.topology.impl.SimpleStream.put(SimpleStream.java:61)
at org.apache.samoa.topology.LocalEntranceProcessingItem.injectNextEvent(LocalEntranceProcessingItem.java:45)
at org.apache.samoa.topology.LocalEntranceProcessingItem.startSendingEvents(LocalEntranceProcessingItem.java:63)
at org.apache.samoa.topology.impl.SimpleTopology.run(SimpleTopology.java:44)
at org.apache.samoa.topology.impl.SimpleEngine.submitTopology(SimpleEngine.java:33)
at org.apache.samoa.LocalDoTask.main(LocalDoTask.java:88)

Process finished with exit code 1"

As for, we’re sending you this e-mail because we need help to figure out how to resolve
this issues in order to run those tasks.


Sincerely, Oscar Henrichs



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