On Fri, Jun 4, 2010 at 8:53 AM, Ted Dunning <[email protected]> wrote:on of the vectors, but isn't strictly necessary. > > Note that since this is an SVD, S is diagonal and all elements are real (and > positive, actually). Thus B* = B.
(Yeah either way it's just dotting stuff with that "diagonal vector", or really the square roots of its values.) > But not customary. The old LSI article makes a better case than I can off > the cuff just before bed. OK sounds like it's best to maintain U sqrt(S) and sqrt(S) V if only for convention. > Actually the elements of S aren't item or user specific. Remember there are > only k non-zeros there. Yeah I meant they're like multipliers for each "feature" (probably not the right word), establishing some relation between pseudo-users's preferences for features and pseudo item's expression of features. > I would guess so, but that would only make sense if they subtracted it ahead > of time. In general, I don't see the point for that. I would rather cosine > normalize each user row. Yeah sounds good. I wouldn't add this step to start.
