Hi Alejandro, you have to provide a detailed description of your benchmark.
There is no such thing is "the efficiency" of a recommender. Mahout offers a wide variety of implementations and components that can be glued together to form a recommender. There are a lot of knobs to adjust that offer trade-offs between execution time, scalability, quality and recency. --sebastian On 15.12.2011 09:30, Alejandro Bellogin Kouki wrote: > Hi all, > > some months ago I performed some efficiency comparisons between the > execution times of one implementation of mine and user- and item-based > CF recommenders in Mahout. By that time, I was using Mahout-0.3 and I > obtained some decent values, taking into account that I was measuring > the average recommendation time per user (that is, how long it took to > execute the method 'recommend(u, N)'). > > Yesterday, I decided to make the same tests with the latest stable > version (Mahout-0.5), and, to my suprise, the execution times in the > latest implementation have been multiplied by a factor of 2. > > Do you have any idea of why is that happening? Is it documented > anywhere? I have specific numbers and code in case you want to check > them out. > > I want to emphasize that I am measuring how much time the recommender > spends on generating a ranking, and, probably, if you have changed how > the plausible items to be recommended for a user are obtained, then this > change may have caused this situation. > > Thank you in advance. > > Best regards, > Alejandro >
