Stephen Becker

Thanks to a two-year fellowship from the Fondation Sciences Mathématiques de Paris, I am at Paris 6 working with Patrick Combettes. Until 2011, I was at Caltech supervised by Emmanuel Candès.

Contact

I am interested in collaborating with mathematicians, scientists and engineers on diverse projects.

Optimization: first-order methods, quasi-Newton methods, primal-dual algorithms
Mathematical applications: compressed sensing and variants, matrix completion and variants (robust PCA…), non-negative matrix factorization and end-member detection, sparse SVM
Physical applications: radar ADC using compressed sensing, quantum tomography, MRI, medical imaging, IMRT, renewable energy

March 2013: I will be joining IBM beginning in Sept 2013 as a Goldstine postdoc

Jan 2013: This website has been redone using jemdoc along with some customizations to the python script. Jemdoc allows content pages to be very simple, and makes using integrating equations into webpages very easy.

Dec 2012: Matlab/Octave code for the 0-SR1 method mentioned in A quasi-Newton proximal splitting method should be available very soon! Please check back.

Aug 2012: Some tips on using Mendeley. I have been using Mendeley to organize my papers for about 3 years now, and I want to share two quick tips that make it work even better. The first is that there is preliminary support in their native PDF viewer to use PDF bookmarks (the kind that work well in Acrobat). To enable this feature, run Mendeley like mendeleydesktop –pdf-toc (for linux; for Windows, it is possible as well but a different command). The second feature is using a more advanced search, and I don't need to describe it because it is covered well in this article on Mendeley search.

June 2012: My preprint Sparse projections onto the simplex with Anastasios Kyrillidis and Volkan Cevher is now available. Accepted in NIPS Workshop on Discrete Optimization in Machine Learning (DISCML) 2012.

June 2012: My preprint A quasi-Newton proximal splitting method with Jalal Fadili is now available. Accepted in NIPS 2012.

May 2012: At SIAM IS ’12 in Philadelphia, I describe a new quasi-Newton method for non-smooth or constrained problems (see the preprint with Jalal Fadili). Slides

Jan 26 2012: Just released TFOCS v.1.1, which is a major update of the old TFOCS release.

Dec 2011: The sparse- and low-rank solver wiki is now online! This replaces the old list of algorithms that I had. The whole world is invited to join and edit the wiki. The benefits of the wiki format are numerous: it can stay up-to-date, it allows anyone in the world to contribute (including people who write algorithms, people who use algorithms, people who are doing background research, etc.).

Sep 2011: I am now at Laboratoire Jacques-Louis Lions at Paris 6, thanks to a grant from the Fondation Sciences Mathematiques de Paris.

May 2011: Final version of my thesis, Practical compressed sensing : modern data acquisition and signal processing, is online.

May 2011: “TFOCS: Flexible First-order Methods for Rank Minimization”, at the Low-rank Matrix Optimization minisymposium at the 2011 SIAM Conference on Optimization in Darmstadt. Here's the RPCA video on youtube (Matlab code to generate this is available at the RPCA demo page).

Sept 2010: “Templates for Convex Cone Problems with Applications to Sparse Signal Recovery” by S. Becker, E. Candès, M. Grant is available. PDF, Software

Jan 2010: I am the TA for ACM 114, Parallel Algorithms for Scientific Applications.

Oct 2009: “Quick intro to convex optimization talk” for ACM^tea. This was split over two weeks, 50 minutes each. Slides

Sept 2009: “Quantum state tomography via compressed sensing” by Gross, Liu, Flammia, Becker and Eisert, is on the arXiv. Link

June 2009: I just started using Mendeley to organize my PDFs. So far, it's exactly what I had been looking for and I highly recommend it. Several other students in my department started using it as well. On a similar note, many people have recommended Dropbox for file storage and syncing, and some collaborators are using it for editing a paper. Edit (2012): I now prefer spideroak but still use Dropbox for legacy reasons. I also tried ubuntu one for a year and was unhappy with it (at least with Ubuntu 10.04).

April 2009: “NESTA: a fast and accurate first-order method for sparse recovery” by S. Becker, J. Bobin and E.J. Candès is on the arXiv. More info at our NESTA website. PDF

Nov 2008: svt.stanford.edu is a software package for Singular Value Thresholding, for Matrix Completion problems. Please email me if you have questions about the software (and include information on the version of Matlab, the operating system, and the hardware – e.g. 32-bit or 64-bit). We are working on making it more compatible with 64-bit systems and compatible with complex-valued data.