The factor matrix Y is used twice in implicit ALS computation, one to compute global Y^T Y, and another to compute local Y_i^T C_i Y_i. -Xiangrui
On Sun, Mar 16, 2014 at 1:18 PM, Matei Zaharia <matei.zaha...@gmail.com> wrote: > On Mar 14, 2014, at 5:52 PM, Michael Allman <m...@allman.ms> wrote: > > I also found that the product and user RDDs were being rebuilt many times > over in my tests, even for tiny data sets. By persisting the RDD returned > from updateFeatures() I was able to avoid a raft of duplicate computations. > Is there a reason not to do this? > > > This sounds like a good thing to add, though I'd like to understand why > these are being recomputed (it seemed that the code would only use each one > once). Do you have any sense why that is? > > Matei
