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Sean Owen commented on MAHOUT-890: ---------------------------------- Do you have a suggested fix, or is it more of an observation? I didn't see a change in the patches. > Performance issue in FPGrowth > ----------------------------- > > Key: MAHOUT-890 > URL: https://issues.apache.org/jira/browse/MAHOUT-890 > Project: Mahout > Issue Type: Bug > Components: Frequent Itemset/Association Rule Mining > Affects Versions: 0.6 > Reporter: tom pierce > Attachments: addSynth.patch, logtrees.patch, smallexample.dat > > > I've encountered a dataset which indicates there is probably a performance > bug lurking in the FPGrowth implementation. This set may be a bit of an > unusual target for FPG - there's a relatively modest number itemsets, and > many items with a Zipfy distribution. I am attaching a patch > (addSynth.patch) to add a similar dataset as > core/src/test/resources/FPGsynth.dat. > FPGsynth.dat can take minutes or a few hours to process, depending on how it > is grouped out to machines. If run in sequential mode, or with "-g 50" it > will take considerable time. Most reducers/"anchor items" are processed > quickly, but a small number take a handful of minutes, and one or two take a > long time. If you experiment with this data, I suggest using '-s 50 -regex > "[ ]+"'. > Digging into this, I've found that the tree pruning code sometimes creates > surprising trees. One oddity I've observed is 0-count nodes, sometimes with > non-zero children. The other is that sometimes subtrees seem to get > repeated. I'm attaching a sample input file (smallexample.dat, use the > whitespace regex with this one, too) and a patch which adds some logging in > pruneFPTree and growthBottomUp which will print out some interesting trees > when run with the smallexample.dat input. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira