Maybe you misunderstood me.
I sent you emails in the past about another recommender of mine (I'm testing 3 
of them). That time the problem was that I was running the first release, that 
contained an older and bugged version of the eval class, so I upgraded to a 
newer version (but still pre-Mahout150) and that solved the problem. 
Changing recommender type, I encounter a DIFFERENT problem.
The reason I can't debug properly is that the ported version of the code (done 
using IKVM that creates dll out of jars) is treated by the c# debugger as a big 
black box so I can debug my own classes, but not mahout's. 


-----Messaggio originale-----
Da: Sean Owen [mailto:[email protected]] 
Inviato: mercoledì 2 settembre 2009 11.21
A: [email protected]
Oggetto: Re: problems evaluating item based recommender

Claudia I believe I've replied to you several times on this mailing
list with possible reasons you are observing this behavior. I am not
clear that you followed up on them, so would point you back to those
first.

You're using a port, of an old version of the code, and we don't have
access to your data, or your code, and you are unable to debug. I am
not sure it is really possible to offer more support then. I strongly
suggest you learn how to run a debugger; it will be extremely useful
here and should point out the cause immediately. It is definitely
possible to debug C#.

It might be useful to compare the port to the current version of these
classes in Java to see if any meaningful changes have occurred that
you might want to re-port.

Mahout 0.2 is probably coming in a month or so. I think this part of
the code is reasonably stable. I don't have any changes planned, and
it's had some time to work out bugs. But I would first encourage you
to get a debugger going rather than update. I don't think it will
'fix' this problem, I think it's a function of your data.

2009/9/2 Claudia Grieco <[email protected]>:
> I'm using an old version of mahout (before the big branch of mahout-150) and
> the evaluation of my item based recommender done with
> GenericRecommenderIRStatsEvaluator doesn't work very well: it always returns
> precision 0 and recall 0. I'm using a port of mahout in C# so I can't debug
> it properly, but I've seen that the program seems to recommend almost the
> same items to everyone and in numerical order (es. 612,613,614.).
>
> What do you think could be the problem?
>
>
>
> (anyway, how much do you think it would take to adjust a program to pass
> from the old version of mahout to the new one? Is there going to be a stable
> new release in the near future?)
>
>

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