Abstract: In this paper, we consider the problem of compressed sensing where the goal is to recover almost all sparse vectors using a small number of fixed linear measurements. For this problem, we propose a novel partial hard-thresholding operator that leads to a general family of iterative algorithms. While
one extreme of the family yields well known hard thresholding algorithms like ITI and HTP[17, 10],
the other end of the spectrum leads to a novel algorithm that we call Orthogonal Matching Pursuit
with Replacement (OMPR). While
one extreme of the family yields well known hard thresholding algorithms like ITI and HTP[17, 10],
the other end of the spectrum leads to a novel algorithm that we call Orthogonal Matching Pursuit
with Replacement (OMPR).While
one extreme of the family yields well known hard thresholding algorithms like ITI and HTP[17, 10],
the other end of the spectrum leads to a novel algorithm that we call Orthogonal Matching Pursuit
with Replacement (OMPR).While
one extreme of the family yields well known hard thresholding algorithms like ITI and HTP[17, 10],
the other end of the spectrum leads to a novel algorithm that we call Orthogonal Matching Pursuit
with Replacement (OMPR). OMPR, like the classic greedy algorithm OMP, adds exactly one coordinate to the support at each iteration, based on the correlation with the current residual. However,
unlike OMP, OMPR also removes one coordinate from the support. This simple change allows us
to prove that OMPR has the best known guarantees for sparse recovery in terms of the Restricted
Isometry Property (a condition on the measurement matrix). . In contrast, OMP is known to have very
weak performance guarantees under RIP. Given its simple structure, we are able to extend OMPR
using locality sensitive hashing to get OMPR-Hash, the first provably sub-linear (in dimensionality)
algorithm for sparse recovery. Our proof techniques are novel and flexible enough to also permit the
tightest known analysis of popular iterative algorithms such as CoSaMP and Subspace Pursuit. We
provide experimental results on large problems providing recovery for vectors of size up to million
dimensions. We demonstrate that for large-scale problems our proposed methods are more robust
and faster than existing methods.
Download: pdf
Citation
- Orthogonal Matching Pursuit with Replacement (pdf, software)
P. Jain, A. Tewari, I. Dhillon.
In Neural Information Processing Systems (NIPS), December 2011.
Bibtex: