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Posted to issues@opennlp.apache.org by "Joern Kottmann (JIRA)" <ji...@apache.org> on 2016/04/29 22:50:12 UTC
[jira] [Commented] (OPENNLP-830) Huge runtime improvement on
training (POS, Chunk, ...)
[ https://issues.apache.org/jira/browse/OPENNLP-830?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15264710#comment-15264710 ]
Joern Kottmann commented on OPENNLP-830:
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I did some tests with the namefinder and came to similar improvement. When the IndexHashTable is replaced with java.util.HashMap it is around 60 - 70 % faster.
Trove4j and HPPC were both slower than java.util.HashMap which is found surprising because they offer Object to Int maps which are more cache friendly (but maybe JVM 8 has some tricks to optimize that).
The parser is around 5%, I didn't test any other components.
I suggest we replace it with the java.util.HashMap.
> Huge runtime improvement on training (POS, Chunk, ...)
> ------------------------------------------------------
>
> Key: OPENNLP-830
> URL: https://issues.apache.org/jira/browse/OPENNLP-830
> Project: OpenNLP
> Issue Type: Improvement
> Components: Machine Learning, POS Tagger
> Affects Versions: 1.6.0
> Environment: Any
> Reporter: Julien Subercaze
> Labels: performance
> Original Estimate: 1h
> Remaining Estimate: 1h
>
> opennlp.tools.ml.model.IndexHashTable is custom-made Hashtable that is used to store mapping index. This Hashtable is heavily used in openlp.tools.ml.* (i.e. every model) and leads to disastrous performance.
> This hashtable is probably legacy some legacy and is highly inefficient. A simple drop-in replacement by a java.util.HashMap wrapper solves the issue, doesn't break compatibility and does not add any dependency.
> Training a pos-tagger on a large dataset with custom tags, I see a factor 5 improvement. It also seems to improve all ML models training pipeline.
> See : https://github.com/jsubercaze/opennlp/blob/trunk/opennlp-tools/src/main/java/opennlp/tools/ml/model/IndexHashTable.java
> For a quick fix.
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