It's an interesting question, and I think the quickest answer is -- what item would be the center of the neighborhood? how would you incorporate a notion of neighborhood?
For users, it's clear: you construct ahead of time a neighborhood of similar users and consider item's they've rated. For item-based recommenders, this idea doesn't exist. It's easy to imagine new algorithms involving a neighborhood of items. Maybe I look at each item a user knows about, construct a neighborhood around that item and do something with it. These aren't canonical algorithms, but you could try them. Sean On Fri, Feb 19, 2010 at 10:51 PM, jamborta <[email protected]> wrote: > > hi, > > just wondering why there is no option to set the neighbourhood size for > item-based recommendation. I had a look at the implementation and it looks > like you take into account all items. is there a reason for that? > > thanks > Tamas > > -- > View this message in context: > http://old.nabble.com/item-based-recommendation-neighbourhood-size-tp27661482p27661482.html > Sent from the Mahout User List mailing list archive at Nabble.com. > >
