In the cross-recommender the similarity matrix is calculated doing [B'A]. We
want the rows to be stored as the item-item similarities in Solr right? [B'B]
is symmetric so just want to make sure I have it straight for [B'A].
B = purchases
iphone ipad nexus galaxy surface
u1 1 1 0 0 0
u2 0 0 1 1 0
u3 0 0 0 0 1
u4 1 1 0 0 0
B' =
u1 u2 u3 u4
iphone 1 0 0 1
ipad 1 0 0 1
nexus 0 1 0 0
galaxy 0 1 0 0
surface 0 0 1 0
A = views
iphone ipad nexus galaxy surface
u1 1 1 1 1 0
u2 1 1 1 1 0
u3 0 0 0 0 1
u4 1 1 1 0 0
[B'A] =
iphone ipad nexus galaxy surface
iphone 2 2 2 1 0
ipad 2 2 2 1 0
nexus 1 1 1 1 0
galaxy 1 1 1 1 0
surface 0 0 0 0 1
The rows are what we want from [B'A] since the row items are from B, right?
