Of course, thank you very much, it's because now my table is almost empty, in this case, do you recommend to me to use an other similarity ?
srowen wrote: > > It doesn't have to do with the mean preference value being 0. > > The problem is that these users overlap in only one item, and so, > Pearson cannot compute a similarity since it cannot define a > correlation coefficient. A correlation would require at least two data > points. Add some more data and you will get non-NaN values. > > On Tue, Jun 23, 2009 at 6:38 PM, charlysf<[email protected]> wrote: >> >> Hello, >> >> I use PearsonCorrelation, and I would like to understand why on my >> example, >> I have a NaN. >> http://www.nabble.com/file/p24175732/Image%2B3.png >> >> http://www.nabble.com/file/p24175732/Image%2B4.png >> >> >> I use PearsonCorrelation for an Item Basis recommender, and I of course >> expect, to have a similarity between the two items, because they are >> linked >> to a same user. >> >> But in fact, I have a NaN. >> >> I saw that the mean of the data should be 0, but or me, 0 is the neutral >> score, and I can't be sure that for each user, their mean is 0, is it >> important ? I don't really understand why. >> >> >> Thank you. >> -- >> View this message in context: >> http://www.nabble.com/Questions-about-PearsonCorrelation-on-a-example-tp24175732p24175732.html >> Sent from the Mahout User List mailing list archive at Nabble.com. >> > > -- View this message in context: http://www.nabble.com/Questions-about-PearsonCorrelation-on-a-example-tp24175732p24175800.html Sent from the Mahout User List mailing list archive at Nabble.com.
