I believe the issue is that the manuscript is lagging the code just a little bit. In 0.3, DenseVector has been separated from implementing Writable, and instead we have DenseVectorWritable which wraps DenseVector and knows how to serialize it.
At least, you will change DenseVector to DenseVectorWritable in the line you quote. Robin is best position to say whether there are other changes. All of which ought be reflected in an upcoming revision to the MEAP chapter drafts of course. Sean On Thu, Mar 4, 2010 at 12:42 PM, tog <[email protected]> wrote: > Dear all, > > Ok I tried 0.2 and it seems to work. Due to some comment on the list > regarding KMean in 0.2 I decided to move to trunk since 0.3 seems > close enough. > Nevertheless I had an issue with the creation of a writer (I am still > in the example of Ch 7 of Mahout in Action). Here is what I got: > > at > org.apache.hadoop.io.serializer.SerializationFactory.getSerializer(SerializationFactory.java:73) > at org.apache.hadoop.io.SequenceFile$Writer.init(SequenceFile.java:910) > at > org.apache.hadoop.io.SequenceFile$Writer.<init>(SequenceFile.java:843) > at > org.apache.hadoop.io.SequenceFile$Writer.<init>(SequenceFile.java:831) > at > org.apache.hadoop.io.SequenceFile$Writer.<init>(SequenceFile.java:823) > > when calling: > > writer = new SequenceFile.Writer(fs, conf, path, LongWritable.class, > DenseVector.class) > > Anyone having the same issue ? > > Regards > Guillaume > > > On Tue, Feb 23, 2010 at 7:14 PM, Alleon Guillaume > <[email protected]> wrote: >> Hi all, >> >> I am a complete newbie in action ... despite I have gone throuh the book of >> the same collection;) >> I would like to classify a number of items - each of them being characterize >> by a number of vectors. I thought it will be a good idea first to classify >> the vectors. Unfortunately my items number keep on growing so what I have >> done so far is a small piece of code constructing the mahout dense vectors >> on the fly setting the name as my item name. As far as I understand those >> vectors are kept in memory ... >> What are the next steps for me ? >> Storing those vectors on disk I assume :) >> Then creating some canopies and then using kmean to create my clusters. >> Can you guide me trough some steps ? >> >> Then I have more questions ? >> Can mahout determine an "optimal" number of clusters ? >> Once a set of clusters exist and new items are added, is it possible to >> update the existing clusters ? Is it possible to add clusters at alower cost >> than recreting it ? >> >> T hanks for your help and time >> Regards >> Guillaume >> > > > > -- > PGP KeyID: 1024D/69B00854 subkeys.pgp.net > > http://cheztog.blogspot.com >
