Diego,Thank you so much for the script. I used it to convert my large text file
to a sequence file. I have been trying to use the sequence file to feed
Mahout's LDA implementation (Mahout 0.7 so the CVB implementation). I first
converted the sequence file to vectors with this, "mahout seq2sparse -i
input/processedaa.seq -o output -ow -wt tf -nr 7" and then ran the LDA with
this, "mahout cvb -i output/tf-vectors -dict output/dictionary.file-0 -o topics
-dt documents -mt states -ow -k 100 --num_reduce_tasks 7 -x 10". The
seq2sparse command produces the tf vectors alright, but the problem is that no
matter what I use for parameters, the LDA job sits at map 0% reduce 0% for an
hour before outputting the error below. It has an error casting Text to
IntWritable. My question is when you said that the key is the line number,
what variable type is the key? Is it Text?
My output..."12/11/11 16:10:50 INFO common.AbstractJob: Command line arguments:
{--convergenceDelta=[0], --dictionary=[output/dictionary.file-0],
--doc_topic_output=[documents], --doc_topic_smoothing=[0.0001],
--endPhase=[2147483647], --input=[output/tf-vectors],
--iteration_block_size=[10], --maxIter=[10], --max_doc_topic_iters=[10],
--num_reduce_tasks=[7], --num_topics=[100], --num_train_threads=[4],
--num_update_threads=[1], --output=[topics], --overwrite=null,
--startPhase=[0], --tempDir=[temp], --term_topic_smoothing=[0.0001],
--test_set_fraction=[0], --topic_model_temp_dir=[states]}12/11/11 16:10:52 INFO
mapred.JobClient: Running job: job_201211111553_000512/11/11 16:10:53 INFO
mapred.JobClient: map 0% reduce 0%12/11/11 17:11:16 INFO mapred.JobClient:
Task Id : attempt_201211111553_0005_m_000003_0, Status :
FAILEDjava.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to
org.apache.hadoop.io.IntWritable at
org.apache.mahout.clustering.lda.cvb.CachingCVB0Mapper.map(CachingCVB0Mapper.java:55)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144) at
org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764) at
org.apache.hadoop.mapred.MapTask.run(MapTask.java:370) at
org.apache.hadoop.mapred.Child$4.run(Child.java:255) at
java.security.AccessController.doPrivileged(Native Method) at
javax.security.auth.Subject.doAs(Subject.java:396) at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.Child.main(Child.java:249)"
Thank you again for your help!Nick
> From: [email protected]
> Date: Thu, 1 Nov 2012 01:07:29 +0100
> Subject: Re: Converting one large text file with multiple documents to
> SequenceFile format
> To: [email protected]
>
> Hei Nick,
> I had exatly the same problem ;)
> I wrote a simple command line utility to create a sequence
> file where each line of the input document is an entry
> (the key is the line number).
>
> https://dl.dropbox.com/u/4663256/tmp/lda-helper.jar
>
> java -cp lda-helper.jar it.cnr.isti.hpc.lda.cli.LinesToSequenceFileCLI
> -input tweets -output tweets.seq
>
> enjoy ;)
> Diego
>
> On Wed, Oct 31, 2012 at 9:30 PM, Charly Lizarralde
> <[email protected]> wrote:
> > I don't think you need that. Just a simple mapper.
> >
> > static class IdentityMapper extends Mapper<LongWritable, Text, Text, Text>
> > {
> >
> > @Override
> > protected void map(LongWritable key, Text value, Context context)
> > throws IOException, InterruptedException {
> >
> > String[] fields = value.toString().split("\t") ;
> > if ( fields.length >= 2) {
> > context.write(new Text(fields[0]), new Text(fields[1]))
> > ;
> > }
> >
> > }
> >
> > }
> >
> > and then run a simple job..
> >
> > Job text2SequenceFileJob = this.prepareJob(this.getInputPath(),
> > this.getOutputPath(), TextInputFormat.class, IdentityMapper.class,
> > Text.class, Text.class, SequenceFileOutputFormat.class) ;
> >
> > text2SequenceFileJob.setOutputKeyClass(Text.class) ;
> > text2SequenceFileJob.setOutputValueClass(Text.class) ;
> > text2SequenceFileJob.setNumReduceTasks(0) ;
> >
> > text2SequenceFileJob.waitForCompletion(true) ;
> >
> > Cheers!
> > Charly
> >
> > On Wed, Oct 31, 2012 at 4:57 PM, Nick Woodward <[email protected]> wrote:
> >
> >>
> >> Yeah, I've looked at filter classes, but nothing worked. I guess I'll do
> >> something similar and continuously save each line into a file and then run
> >> seqdiretory. The running time won't look good, but at least it should
> >> work. Thanks for the response.
> >>
> >> Nick
> >>
> >> > From: [email protected]
> >> > Date: Tue, 30 Oct 2012 18:07:58 -0300
> >> > Subject: Re: Converting one large text file with multiple documents to
> >> SequenceFile format
> >> > To: [email protected]
> >> >
> >> > I had the exact same issue and I tried to use the seqdirectory command
> >> with
> >> > a different filter class but It did not work. It seems there's a bug in
> >> the
> >> > mahout-0.6 code.
> >> >
> >> > It ended up as writing a custom map-reduce program that performs just
> >> that.
> >> >
> >> > Greetiings!
> >> > Charly
> >> >
> >> > On Tue, Oct 30, 2012 at 5:00 PM, Nick Woodward <[email protected]>
> >> wrote:
> >> >
> >> > >
> >> > > I have done a lot of searching on the web for this, but I've found
> >> > > nothing, even though I feel like it has to be somewhat common. I have
> >> used
> >> > > Mahout's 'seqdirectory' command to convert a folder containing text
> >> files
> >> > > (each file is a separate document) in the past. But in this case there
> >> are
> >> > > so many documents (in the 100,000s) that I have one very large text
> >> file in
> >> > > which each line is a document. How can I convert this large file to
> >> > > SequenceFile format so that Mahout understands that each line should be
> >> > > considered a separate document? Would it be better if the file was
> >> > > structured like so....docId1 {tab} document textdocId2 {tab} document
> >> > > textdocId3 {tab} document text...
> >> > >
> >> > > Thank you very much for any help.Nick
> >> > >
> >>
> >>
>
>
>
> --
> Computers are useless. They can only give you answers.
> (Pablo Picasso)
> _______________
> Diego Ceccarelli
> High Performance Computing Laboratory
> Information Science and Technologies Institute (ISTI)
> Italian National Research Council (CNR)
> Via Moruzzi, 1
> 56124 - Pisa - Italy
>
> Phone: +39 050 315 3055
> Fax: +39 050 315 2040
> ________________________________________
