Getting recommendation for a new user

[pierre-henri]

Hi,

Imagine you have trained a recommender with a corpus of (user, item)...for instance with ItemKNN recommender..then saving the model.

Now you want to have a recommendation for new user (who does not belong to the training set) but who have watched/liked items belongng to your training set (you have the histor of the user :logs like new (user, item)...)

How do you get recommendation with mymedialite for this new user (taking into account his history)

BR

[Zeno Gantner]

Hello,

no user history means no personalization for that user.

You could return the most popular items, maybe a bit randomized.

Cheers,

   Z.

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[pierre-henri]

Hello,

This user has a history.

The model saved had been trained for instance for userid from 1 to 1000. Now comes the user 1001 with an history (a list of items) , how can I user the model saved to make prediction ?

Of course the items of this user's history belong to the set of Items on which the recommender has been trained.

BR

[pierre-henri]

By browsing the Q&A, I have found that I want is following:

"What you want is a technique called fold-in:
Given the model and a new user and his interactions, compute
recommendations for that user. It is already supported in MyMediaLite
for rating prediction (see the discussion in this group earlier this
year).
For item recommendation, there is already an interface defined, but
none of the recommenders implement the interface:
https://github.com/zenogantner/MyMediaLite/blob/master/src/MyMediaLite/ItemRecommendation/IFoldInItemRecommender.cs

If we know that it is a desired feature, it will get higher priority.
On the other hand, contributions in this area are also welcome ;-)"

Is it implemented  for item_recommendation (on command line)?

BR

[Zeno Gantner]

Gotcha, sorry for mis-reading your prior e-mail.

This is supported, and called fold-in.
See the IFoldInItemRecommender interface.

https://github.com/zenogantner/MyMediaLite/blob/master/src/MyMediaLite/ItemRecommendation/IFoldInItemRecommender.cs

Cheers,
Z.

[Zeno Gantner]

Not implemented for the command-line tool.

You'd need to code it yourself, either standalone, or add it to the
command line tool.

Cheers,
Z.