I've recently started working with Mahout. At first, I tried the
trunk,
which I got to compile (both from within Eclipse with a Maven
plugin, and
command line), but which apparently is in a state of flux regarding
building
and running the examples (?).
I tried running the Twentynewsgroups classification example, after
copying
the relevant Maven file to the examples directory, as suggested
on the
mailing list some time ago. I could get the example's data set from
wikipedia, could get it processed into input data located on the
single-node/local hdfs, and could get a model trained and output
to that
hdfs. However, the example class TestClassifierto test with the
trained
model didn't work for me, neither in mapreduce nor in sequential
mode. In
the mapreduce case, and even with quite high JVM maximum heap
sizes (I
tried
2048), I get heapspace out of memory errors / object configuration
errors.
In the sequential case, I seemingly get 0 items classified, see
output
below. (Note that I reduced the data set to just 8 instead of 20
newsgroups,
thinking the data size might have something to do with the
problem.)
I also tried release 0.2, which I got to compile and for which I
got the
example running more easily, but still with the same errors when
testing
with the trained model. Any ideas what might be going wrong, or
what I
might
be doing wrong?
Kind regards,
Loek Cleophas
Output of TestClassifier:
bin/hadoop jar
~/Downloads/mahout-0.2/examples/target/mahout-examples-0.2.job
org.apache.mahout.classifier.bayes.TestClassifier -m
8newsmodel-0.2 -d
8newsInput -ng 3 -type bayes -source hdfs -method sequential
<... reading all the feature weights ...>
10/01/13 10:22:08 INFO io.SequenceFileModelReader: Read 1950000
feature
weights
10/01/13 10:22:11 INFO io.SequenceFileModelReader:
hdfs://localhost:9000/user/loekcleophas/8newsmodel-0.2/trainer-
weights/Sigma_k/part-00000
10/01/13 10:22:11 INFO io.SequenceFileModelReader:
hdfs://localhost:9000/user/loekcleophas/8newsmodel-0.2/trainer-
weights/Sigma_kSigma_j/part-00000
10/01/13 10:22:11 INFO io.SequenceFileModelReader:
420716.6056712613
10/01/13 10:22:11 INFO io.SequenceFileModelReader:
hdfs://localhost:9000/user/loekcleophas/8newsmodel-0.2/trainer-
thetaNormalizer/part-00000
10/01/13 10:22:11 INFO io.SequenceFileModelReader:
hdfs://localhost:9000/user/loekcleophas/8newsmodel-0.2/trainer-
tfIdf/trainer-tfIdf/part-00000
comp.windows.x -4443829.798557077 7727496.583973498
-0.5750671967650419
comp.graphics -3252365.124498224 7727496.583973498
-0.4208821174044246
soc.religion.christian -5106741.34456479 7727496.583973498
-0.6608532645819548
alt.atheism -3447983.6168798 7727496.583973498 -0.44619671835646907
misc.forsale -2276588.3662840202 7727496.583973498
-0.2946087832643716
comp.sys.mac.hardware -2445489.855812473 7727496.583973498
-0.31646598988918556
comp.os.ms-windows.misc -7727496.583973498 7727496.583973498 -1.0
comp.sys.ibm.pc.hardware -2687646.590023761 7727496.583973498
-0.3478030123750332
10/01/13 10:23:17 INFO bayes.TestClassifier:
nCalls = 0;
sumTime = 0.0s;
minTime = 0.0ms;
maxTime = 0.0ms;
meanTime = 0.0ms;
stdDevTime = 0.0ms;
10/01/13 10:23:18 INFO bayes.TestClassifier:
=======================================================
Summary
-------------------------------------------------------
Correctly Classified Instances : 0 ?%
Incorrectly Classified Instances : 0 ?%
Total Classified Instances : 0
=======================================================
Confusion Matrix
-------------------------------------------------------
a b c d e f g h
<--Classified as
0 0 0 0 0 0 0 0
| 0
a = comp.windows.x
0 0 0 0 0 0 0 0
| 0
b = comp.graphics
0 0 0 0 0 0 0 0
| 0
c = soc.religion.christian
0 0 0 0 0 0 0 0
| 0
d = alt.atheism
0 0 0 0 0 0 0 0
| 0
e = misc.forsale
0 0 0 0 0 0 0 0
| 0
f = comp.sys.mac.hardware
0 0 0 0 0 0 0 0
| 0
g = comp.os.ms-windows.misc
0 0 0 0 0 0 0 0
| 0
h = comp.sys.ibm.pc.hardware
Default Category: unknown: 8
