It does appear that recent changes have broken KMeans. Removing the "/*"
makes the example work but won't work in general if there is more than
one reducer specified. For that, the "part-0000" in the calling location
needs to be removed so that isConverged() can iterate over all of the
cluster part files produced by the reducers. The unit test
'testKMeansMRJob' throws the same exception, but something must be
handling that exception because the test passes for some reason.
I will have some time to look into this in a day or so but in the mean
time perhaps the folks who have been doing all the KMeans changes can
figure it out.
Jeff
nfantone wrote:
This error is still bugging me. The exception:
WARNING: java.io.FileNotFoundException: File
output/clusters-0/part-00000/* does not exist.
java.io.FileNotFoundException: File output/clusters-0/part-00000/*
does not exist.
ocurrs first at:
org.apache.mahout.clustering.kmeans.KMeansDriver.isConverged(KMeansDriver.java:298)
which corresponds to:
private static boolean isConverged(String filePath, JobConf conf,
FileSystem fs)
throws IOException {
Path outPart = new Path(filePath + "/*");
SequenceFile.Reader reader = new SequenceFile.Reader(fs, outPart,
conf); <-- THIS
...
}
where isConverged() is called in this fashion:
return isConverged(clustersOut + "/part-00000", conf, fs);
by runIteration(), which is previously invoked by runJob() like:
String clustersOut = output + "/clusters-" + iteration;
converged = runIteration(input, clustersIn, clustersOut, measureClass,
delta, numReduceTasks, iteration);
Consequently, assuming its the first iteration and the output folder
has been named "output" by the user, the SequenceFile.Reader receives
"output/clusters-0/part-00000/*" as a path, which is non-existent. I
believe the path should end in "part-00000" and the + "/*" should be
removed... although someone, evidently, thought otherwise.
Any feedback?
On Mon, Jul 6, 2009 at 5:39 PM, nfantone<[email protected]> wrote:
I was using Canopy to create input clusters, but the error appeared
while running kMeans (if I run kMeans' job only with previously
created clusters from Canopy placed in output/canopies as initial
clusters, it still fails). I noticed no other problems. I was using
revision 790979 before updating. Strangely, there were no changes in
the job and drivers class from that revision. svn diff shows that the
only classes that changed in org.apache.mahout.clustering.kmeans
package were KMeansInfo.java and RandomSeedGenerator.java
On Mon, Jul 6, 2009 at 3:55 PM, Jeff Eastman<[email protected]> wrote:
Hum, no, it's looking for the output of the first iteration. Were there
other errors? What was the last revision you were running? It does look like
something got horked, as it should be looking for output/clusters-0/*. Can
you diff the job and driver class to see what changed?
Jeff
nfantone wrote:
Fellows, today I updated to revision 791558 and while running kMeans I
got the following exception:
WARNING: java.io.FileNotFoundException: File
output/clusters-0/part-00000/* does not exist.
java.io.FileNotFoundException: File output/clusters-0/part-00000/*
does not exist.
The algorithm isn't interrupted, though. But this exception wasn't
thrown before the update and, to me, its message is not quite clear.
It seems as it's looking for any file inside a "part-00000" directory,
which doesn't exist; and, as far as I know, "part-xxxxx" are default
names for output files.
I could show the entire stack trace, if needed. Any pointers?
On Thu, Jul 2, 2009 at 3:16 PM, nfantone<[email protected]> wrote:
Thanks for the feedback, Jeff.
The logical format of input to KMeans is <Key, Vector> as it is in
sequence
file format, but the Key is never used. To my knowledge, there is no
requirement to assign identifiers to the input points*. Users are free
to
associate an arbitrary name field with each vector - also label mappings
may
be assigned - but these are not manipulated by KMeans or any of the
other
clustering applications. The name field is now used as a vector
identifier
by the KMeansClusterMapper - if it is non-null - in the output step
only.
The key may not be used internally, but externally they can prove to
be pretty useful. For me, keys are userIDs and each Vector represents
his/her historical behavior. Being able to collect the output
information as <UserID, ClusterID> is quite neat as it allows me to,
for instance, retrieve user information using data directly from a
HDFS file's field.
