“…For example, there are variants on alternating minimization (with alternating least squares as a special case) [DLYT76, YDLT76, TYDL77, DL84, DLM09], alternating Newton methods [Gor02,SG08], (stochastic or incremental) gradient descent [KO09, LRS + 10, NRRW11, RRWN11, BRRT12, YYH + 13, RR13], conjugate gradients [RS05,SJ03], expectation minimization (EM) (or "soft-impute") methods [TB99,SJ03,MHT10,HMLZ14], multiplicative updates [LS99], and convex relaxations to semidefinite programs [SRJ04,FHB04,RFP10,FM13].…”