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Poster
Wed Jul 11 09:15 AM -- 12:00 PM (PDT) @ Hall B #94
On Learning Sparsely Used Dictionaries from Incomplete Samples
Thanh Nguyen · Akshay Soni · Chinmay Hegde
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Existing algorithms for dictionary learning assume that the entries of the (high-dimensional) input data are fully observed. However, in several practical applications, only an incomplete fraction of the data entries may be available. For incomplete settings, no provably correct and polynomial-time algorithm has been reported in the dictionary learning literature. In this paper, we provide provable approaches for learning -- from incomplete samples -- a family of dictionaries whose atoms have sufficiently ``spread-out'' mass. First, we propose a descent-style iterative algorithm that linearly converges to the true dictionary when provided a sufficiently coarse initial estimate. Second, we propose an initialization algorithm that utilizes a small number of extra fully observed samples to produce such a coarse initial estimate. Finally, we theoretically analyze their performance and provide asymptotic statistical and computational guarantees.