Matrix completion from a few entries

  • Authors:
  • Raghunandan H. Keshavan;Andrea Montanari;Sewoong Oh

  • Affiliations:
  • Department of Electrical Engineering, Stanford University, Stanford, CA;Department of Electrical Engineering and Departments of Statistics, Stanford University, Stanford, CA;Department of Electrical Engineering, Stanford University, Stanford, CA

  • Venue:
  • IEEE Transactions on Information Theory
  • Year:
  • 2010

Quantified Score

Hi-index 754.85

Visualization

Abstract

Let M be an nα×n matrix of rank r, and assume that a uniformly random subset E of its entries is observed. We describe an efficient algorithm, which we call OPTSPACE, that reconstructs M from |E| = O(r n) observed entries with relative root mean square error RMSE ≤ C(α)(nr/|E|)1/2 with probability larger than 1 - 1/n3. Further, if r = O(1) and M is sufficiently unstructured, then OPTSPACE reconstructs it exactly from |E| = O(n log n) entries with probability larger than 1 - 1/n3. This settles (in the case of bounded rank) a question left open by Candès and Recht and improves over the guarantees for their reconstruction algorithm. The complexity of our algorithm is O(|E|r log n), which opens the way to its use for massive data sets. In the process of proving these statements, we obtain a generalization of a celebrated result by Friedman-Kahn-Szemerédi and Feige-Ofek on the spectrum of sparse random matrices.