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From Sean Owen <>
Subject Re: problems with taste.
Date Wed, 15 Jul 2009 10:16:55 GMT
OK, hmm well it was kind of a long shot anyway. It should have worked even so.

I see one data file attached. There are some blank lines at the top,
though I don't think that will matter.

You are putting quotes around the names. That means the item IDs have
quotes in their names, which is not what I think you intend. For
example, you do not have an item named 'red', you have an item named
'"red"' in your model. If you are looking for recommendations that
include the item 'red' you will not find any. But somehow I suspect
this is not the problem you are talking about.

What algorithm are you using -- one involving a correlation-based
similarity metric like Pearson? I ask because most of your ratings
have exactly the same rating, which will cause correlations to be
undefined in some cases. You also have relatively little data. It may
be that there are simply few or no defined similarities between users
in the model and so no recommendations can be made.

Add more, or more realistic, data and you should see better results perhaps.

But I still then can't explain why two copies of the same file give
different results. I might have to see the code.
Yes do not send anything confidential.

On Wed, Jul 15, 2009 at 11:10 AM, Laya Patwa<> wrote:
> Hey!
> I followed your instructions. It doesn't work even when I put each file in
> separate directory.
> Maybe you should have a look at the code and the data files. I am attaching
> 2 of the data files. I need to get permission for the 3rd one( it is also a
> bit larger ). The code is almost the same as given in the documentation. It
> is giving recommendations for the file testdata.csv.
> Cheers,
> Laya
> On Wed, Jul 15, 2009 at 11:43 AM, Sean Owen <> wrote:
>> Hmm, I might have guessed there is some file encoding issues, related
>> to line breaks, since you say copying the file "breaks" it. But that
>> would explain, I think, why a copy would *work* rather than fail.
>> One thing to be careful of is that FileDataModel tries to be clever
>> and allow you to post incremental updates to the data file by placing
>> similarly-named files in the same directory. How have you named your
>> files? To rule this out, put the files in separate directories, just
>> to make sure.
>> Otherwise perhaps you can send me a sample of the data file or a
>> sample of your code to see what is going on.
>> On Wed, Jul 15, 2009 at 10:23 AM, Laya Patwa<>
>> wrote:
>> > Hi!
>> > I am a student and right now I am working on a project named CoEUD. My
>> > task
>> > is to build a recommender system and I am using the taste recommender
>> > library that comes with mahout.
>> >
>> > I downloaded the subversion and installed it using maven and cygwin on
>> > windows and also on MacOS. I tried the grouplens demo that is given in
>> > the
>> > taste documentation and it also worked. Then I tried the example for
>> > user
>> > based recommender, but it is giving some problems as follows:
>> > 1) I have 3 different data files with me and they are in CSV format
>> > having
>> > values of userID, itemID and preference. The recommendations are
>> > generated
>> > for 1 data file and not for the others. There are no errors. The program
>> > runs and generates an empty recommendation list for other data files
>> > 2)Another peculiar thing that is happening is that when I make a copy of
>> > the
>> > data file for which the user based recommender example is working and
>> > use
>> > this data file, the recommendation list generated is empty.
>> >
>> > I am stuck with the above 2 problems and can't figure out why the
>> > recommendations are not generated for all the data files. Can you please
>> > help me out.
>> >
>> > I am using eclipse.
>> >
>> > Cheers,
>> > Laya
>> >

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