Yes, there is still a lot of work to do =P 
As Ted said, Decision Forests classifier should ultimately have a similar 
interface to all Mahout classifiers.


> 1. how can I output the model and how can I use the trained model to 
> predict

I should commit a patch really soon (this Saturday ?) that will allow you to 
save the trained model and use it to claffiy new data


> 2. There is also no option to specify number of random
> features for each tree. How can I adjust that parameter?

the -sl parameter allows you to specify the number of random features the 
trainer will randomly select for each tree node. Is this what you are looking 
for ?


> I think there is still no enough parameters options to use, at least not
> enough as R's

I'll love to hear any suggestion/addition you want me to make. I already have a 
lot of features I want to add, but I could use your (the users) feedback to 
know which feature I should start working on first. =D

--- En date de : Ven 12.3.10, Cui tony <[email protected]> a écrit :

> De: Cui tony <[email protected]>
> Objet: Re: New to mahout
> À: [email protected]
> Date: Vendredi 12 mars 2010, 2h43
> 1. You can check the example java
> code in trunk : BuildForest.java and
> TestForest.java.
> 
> 2. I think there is still no enough parameters options to
> use, at least not
> enough as R's
> 
> 2010/3/12 Yang Sun <[email protected]>
> 
> > Thanks for the reply. The trunk version runs without
> any problem. I still
> > have a couple questions about the method.
> >
> > 1. how can I output the model and how can I use the
> trained model to
> > predict
> > classes of new data? I saw the options of the class:
> >
> > Options
> >  --data (-d) path       
>            Data path
> >  --dataset (-ds) dataset     
>       Dataset path
> >  --iterations (-i) numIterations   
> Number of times to repeat the test
> >  --nbtrees (-t) nbtrees     
>        Number of trees to grow,
> each iteration
> >  --help (-h)         
>               Print out
> help
> >
> > It seems no option for specifying output directory on
> Hadoop.
> >
> > 2. There is also no option to specify number of random
> features for each
> > tree. How can I adjust that parameter?
> >
> > Thanks
> >
> > On Thu, Mar 11, 2010 at 10:29 AM, Ted Dunning <[email protected]>
> > wrote:
> >
> > > Try using the trunk version.  We are about
> to release 0.3 and it has
> > > significant improvements.
> > >
> > > On Thu, Mar 11, 2010 at 9:40 AM, Yang Sun <[email protected]>
> > wrote:
> > >
> > > > Hi,
> > > >
> > > > It's the first time I try to use mahout. But
> the Breiman example gave
> > me
> > > > the
> > > > following exception:
> > > >
> > > > [localhost]$ hadoop jar
> examples/target/mahout-examples-0.2.job
> > > > org.apache.mahout.df.BreimanExample -d
> test_data/glass.data -ds
> > > test_data/
> > > > glass.info -i 10 -t 100
> > > > 10/03/11 09:26:07 INFO df.BreimanExample:
> Iteration 0
> > > > 10/03/11 09:26:07 INFO df.BreimanExample:
> Growing a forest with m=4
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 10%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 20%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 30%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 40%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 50%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 60%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 70%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 80%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 90%
> > > > 10/03/11 09:26:07 INFO
> ref.SequentialBuilder: Building 100%
> > > > Exception in thread "main"
> java.lang.IllegalArgumentException:
> > > > labels.length
> > > > != predictions.length
> > > >        at
> > > >
> org.apache.mahout.df.ErrorEstimate.errorRate(ErrorEstimate.java:29)
> > > >        at
> > > >
> >
> org.apache.mahout.df.BreimanExample.runIteration(BreimanExample.java:108)
> > > >        at
> > >
> org.apache.mahout.df.BreimanExample.run(BreimanExample.java:214)
> > > >        at
> org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
> > > >        at
> > >
> org.apache.mahout.df.BreimanExample.main(BreimanExample.java:143)
> > > >        at
> sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> > > >        at
> > > >
> > > >
> > >
> >
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> > > >        at
> > > >
> > > >
> > >
> >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> > > >        at
> java.lang.reflect.Method.invoke(Method.java:597)
> > > >        at
> org.apache.hadoop.util.RunJar.main(RunJar.java:156)
> > > >
> > > > Can any one help me get through it?
> > > >
> > > > Thanks,
> > > > Yang
> > > >
> > >
> >
> 



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