Subject: Mahout beginner questions...

Not really.  See my previous posting.

The best way to get fast recommendations is to use an item-based
recommender.  Pre-computing recommendations for all users is not usually a
win because you wind up doing a lot of wasted work and you still don't have
anything for new users who appear between refreshes.  If you build up a
service to handle the new users, you might as well just serve all users
from that service so that you get up to date recommendations for everyone.

There IS a large off-line computation.  But that doesn't produce
recommendations for USER's.  It typically produces recommendations for
ITEM's.  Then those item-item recommendations are combined to produce
recommendations for users.

On Sun, Mar 25, 2012 at 12:28 PM, Razon, Oren <[EMAIL PROTECTED]> wrote: