Sample-Efficient Low Rank Phase Retrieval
This work studies the Low Rank Phase Retrieval (LRPR) problem: recover an <inline-formula> <tex-math notation="LaTeX">n \times q </tex-math></inline-formula> rank-<inline-formula> <tex-math notation="LaTeX">r </tex-math></inline-formul...
Saved in:
| Published in: | IEEE transactions on information theory Vol. 67; no. 12; pp. 8190 - 8206 |
|---|---|
| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
New York
IEEE
01.12.2021
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Subjects: | |
| ISSN: | 0018-9448, 1557-9654 |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | This work studies the Low Rank Phase Retrieval (LRPR) problem: recover an <inline-formula> <tex-math notation="LaTeX">n \times q </tex-math></inline-formula> rank-<inline-formula> <tex-math notation="LaTeX">r </tex-math></inline-formula> matrix <inline-formula> <tex-math notation="LaTeX">{ \boldsymbol {X}^{\ast}} </tex-math></inline-formula> from <inline-formula> <tex-math notation="LaTeX">\boldsymbol {y}_{k} = | \boldsymbol {A}_{k}^\top \boldsymbol {x}^{\ast} _{k}| </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">k=1, 2,\ldots, q </tex-math></inline-formula>, when each <inline-formula> <tex-math notation="LaTeX">\boldsymbol {y}_{k} </tex-math></inline-formula> is an m-length vector containing independent phaseless linear projections of <inline-formula> <tex-math notation="LaTeX">\boldsymbol {x}^{\ast}_{k} </tex-math></inline-formula>. Here <inline-formula> <tex-math notation="LaTeX">|.| </tex-math></inline-formula> takes element-wise magnitudes of a vector. The different matrices <inline-formula> <tex-math notation="LaTeX">\boldsymbol {A}_{k} </tex-math></inline-formula> are i.i.d. and each contains i.i.d. standard Gaussian entries. We obtain an improved guarantee for AltMinLowRaP, which is an Alternating Minimization solution to LRPR that was introduced and studied in our recent work. As long as the right singular vectors of <inline-formula> <tex-math notation="LaTeX">{ \boldsymbol {X}^{\ast}} </tex-math></inline-formula> satisfy the incoherence assumption, we can show that the AltMinLowRaP estimate converges geometrically to <inline-formula> <tex-math notation="LaTeX">{ \boldsymbol {X}^{\ast}} </tex-math></inline-formula> if the total number of measurements <inline-formula> <tex-math notation="LaTeX">mq \gtrsim nr^{2} (r + \log (1/\epsilon)) </tex-math></inline-formula>. In addition, we also need <inline-formula> <tex-math notation="LaTeX">m \gtrsim max(r, \log q, \log n) </tex-math></inline-formula> because of the specific asymmetric nature of our problem. Compared to our recent work, we improve the sample complexity of the AltMin iterations by a factor of <inline-formula> <tex-math notation="LaTeX">r^{2} </tex-math></inline-formula>, and that of the initialization by a factor of <inline-formula> <tex-math notation="LaTeX">r </tex-math></inline-formula>. We argue, based on comparison with related well-studied problems, why the above sample complexity cannot be improved any further for non-convex solutions to LRPR. We also extend our result to the noisy case; we prove stability to corruption by small additive noise. |
|---|---|
| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 |
| ISSN: | 0018-9448 1557-9654 |
| DOI: | 10.1109/TIT.2021.3112805 |