I will think further but in the current implicit formulation with confidence, looks like I am factorizing a 0/1 matrix with weights 1 + alpha*rating for observed (1) values and 1 for unobserved (0) values. It's a bit different from LSA model.
>> On Sun, Jul 26, 2015 at 6:45 AM, Debasish Das <debasish.da...@gmail.com> >> wrote: >> > Hi, >> > >> > Implicit factorization is important for us since it drives >> recommendation >> > when modeling user click/no-click and also topic modeling to handle 0 >> counts >> > in document x word matrices through NMF and Sparse Coding. >> > >> > I am a bit confused on this code: >> > >> > val c1 = alpha * math.abs(rating) >> > if (rating > 0) ls.add(srcFactor, (c1 + 1.0)/c1, c1) >> > >> > When the alpha = 1.0 (high confidence) and rating is > 0 (true for word >> > counts), why this formula does not become same as explicit formula: >> > >> > ls.add(srcFactor, rating, 1.0) >> > >> > For modeling document, I believe implicit Y'Y needs to stay but we need >> > explicit ls.add(srcFactor, rating, 1.0) >> > >> > I am understanding confidence code further. Please let me know if the >> idea >> > of mapping implicit to handle 0 counts in document word matrix makes >> sense. >> > >> > Thanks. >> > Deb >> > >> > >
