use
“mahout itemsimilarity …”
But be aware that you have to convert all your user and item ids into non-negative ints. Basically
inside Mahout-MapReduce they are assumed to be row and column numbers in a big matrix of all
input.
BTW no need to move data, Mahout-Spark reads anything Mahout-MapReduce can read without the
ID restrictions.
On Apr 12, 2015, at 8:04 PM, lastarsenal <lastarsenal@163.com> wrote:
Hi, Pat,
I think it would better to follow the existing system instead of making a large scale data
transfer.
So, I will be very appreciated if somebody can give the advice based on hadoop, Thank you.
在 2015-04-13 00:33:48，"Pat Ferrel" <pat@occamsmachete.com> 写道：
> You are invoking it incorrectly but I’d suggest using the newer Spark version. It’s
easier to use and about 10x faster.
>
> You’ll need to install Spark alongside Mahout then invoke with:
>
> mahout spark-itemsimilarity -i input -o output ….
>
> The driver is documented here: http://mahout.apache.org/users/algorithms/intro-cooccurrence-spark.html
>
>
> On Apr 11, 2015, at 12:34 AM, lastarsenal <lastarsenal@163.com> wrote:
>
> Hi,
>
> I'm a rookie for mahout. Recently when I tried to run ItemSimilarityJob with my own hadoop,
I met a problem. The command is:
>
> hadoop jar mahout-core-0.9-job.jar org.apache.mahout.cf.taste.hadoop.similarity.item.ItemSimilarityJob
-i /home/hadoop/itembased/user_item -o /home/hadoop/itembased/output -s SIMILARITY_EUCLIDEAN_DISTANCE
-mp 0 -b true --startPhase 0 --endPhase 0
>
>
> There are 1 errors:
> 15/04/10 15:06:02 ERROR common.AbstractJob: Unexpected 0 while processing Job-Specific
Options:
> Unexpected 0 while processing Job-Specific Options:
> Usage:
> [--input <input> --output <output> --similarityClassname <similarityClassname>
> --maxSimilaritiesPerItem <maxSimilaritiesPerItem> --maxPrefs <maxPrefs>
> --minPrefsPerUser <minPrefsPerUser> --booleanData <booleanData> --threshold
> <threshold> --randomSeed <randomSeed> --help --tempDir <tempDir> --startPhase
> <startPhase> --endPhase <endPhase>]
>
>
> What's the resaon for this situation? Thank you!
>
>
> Best Regards,
> lastarsenal
>
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