We consider moment matching techniques for estimation in Latent Dirichlet
Allocation (LDA). By drawing explicit links between LDA and discrete versions
of independent component analysis (ICA), we first derive a new set of
cumulant-based tensors, with an improved sample complexity. Moreover, we reuse
standard ICA techniques such as joint diagonalization of tensors to improve
over existing methods based on the tensor power method. In an extensive set of
experiments on both synthetic and real datasets, we show that our new
combination of tensors and orthogonal joint diagonalization techniques
outperforms existing moment matching methods.Comment: 30 pages; added plate diagrams and clarifications, changed style,
corrected typos, updated figures. in Proceedings of the 29-th Conference on
Neural Information Processing Systems (NIPS), 201
