Descent methods for Nonnegative Matrix Factorization
  In this paper, we present several descent methods that can be applied to nonnegative matrix factorization and we analyze a recently developped fast block coordinate method called Rank-one Residue Iteration (RRI). We also give a comparison of these different methods and show that the new block coordinate method has better properties in terms of approximation error and complexity. By interpreting this method as a rank-one approximation of the residue matrix, we prove that it \emph{converges} and also extend it to the nonnegative tensor factorization and introduce some variants of the method by imposing some additional controllable constraints such as: sparsity, discreteness and smoothness. 
Ngoc-Diep Ho (1), Paul Van Dooren (1) and Vincent D. Blondel (1) ((1)   Universit\'e catholique de Louvain, Belgium)