“…In [14], the authors proposed a multipath hierarchical matching pursuit to learn features by capturing multiple aspects of discriminative structures of the data in a deep path architecture. Algorithms in [15] and [16] are tree search based methods which use different deep tree search strategies during feature selection and estimation procedures to improve the sparse approximation. In [17], the authors proposed a learned OMP algorithm for fast sparse approximation by learning a single hidden neural network for subspace clustering.…”