sparse pca
play

Sparse PCA refusing to graduate :-) Aviad Rubinstein (UC Berkeley) - PowerPoint PPT Presentation

Best* Case Approximability of Sparse PCA refusing to graduate :-) Aviad Rubinstein (UC Berkeley) Joint work with Siu-On Chan and Dimitris Papailliopoulos Sparse Principal Component Analysis max s.t. 2 = 1 and 0


  1. Best* Case Approximability of Sparse PCA refusing to graduate :-) Aviad Rubinstein (UC Berkeley) Joint work with Siu-On Chan and Dimitris Papailliopoulos

  2. Sparse Principal Component Analysis max 𝑦 ⊤ 𝐵𝑦 s.t. 𝑦 2 = 1 and 𝑦 0 ≤ 𝑙 (and 𝐵 is PSD) 7.1 1.3 ⋯ 4.5 −2.6 −3.4 ⋯ 6.2 ⋮ ⋮ ⋱ ⋮ 3.1 9.2 ⋯ −4.8 “Yes we SPCA!” -Obama, 2008

  3. Sparse Spiked Covariance Model (“average case”) rank 1 ⋯ 0 𝑙 × 𝑙 block 𝐵 = 𝐽 𝑜 + +noise ⋮ ⋱ ⋮ 0 ⋯ 0 • Cool sample-complexity / computational-complexity tradeoff [Berthet & Rigollet ’13 , Wang et al ’14 , Gao et al ’15 , Kraugthgamer et al ’15 , Ma & Wigderson ’15] • Good news: trivial algorithm gives (1 − 𝑝 1 ) -approximation • Bad news: this is not what your data looks like!

  4. Our results: “best - case” analysis Computationally intractable even when given the exact covariance matrix: • NP-hard to approximate to within (1 − 𝜗) • SSE-hard to approximate to within any 𝑑 • Quasi-quasi-poly ( 𝑓 𝑓 lnln𝑜 ) integrality gap • 𝑜 −1/3 -approximation algorithm “Vive la SPCA!” -Napoleon, 1808

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend