sp-2
Random Quadratic Forms with Dependence: Applications to Restricted Isometry and Beyond
Arindam Banerjee, Qilong Gu, Vidyashankar Sivakumar, Steven Z. Wu
Several important families of computational and statistical results in machine learning and randomized algorithms rely on uniform bounds on quadratic forms of random vectors or matrices. Such results include the Johnson-Lindenstrauss (J-L) Lemma, the Restricted Isometry Property (RIP), randomized sketching algorithms, and approximate linear algebra. The existing results critically depend on statistical independence, e.g., independent entries for random vectors, independent rows for random matrices, etc., which prevent their usage in dependent or adaptive modeling settings. In this paper, we show that such independence is in fact not needed for such results which continue to hold under fairly general dependence structures. In particular, we present uniform bounds on random quadratic forms of stochastic processes which are conditionally independent and sub-Gaussian given another (latent) process. Our setup allows general dependencies of the stochastic process on the history of the latent process and the latent process to be influenced by realizations of the stochastic process. The results are thus applicable to adaptive modeling settings and also allows for sequential design of random vectors and matrices. We also discuss stochastic process based forms of J-L, RIP, and sketching, to illustrate the generality of the results.
Random Quadratic Forms with Dependence: Applications to Restricted Isometry and Beyond
Banerjee, Arindam, Gu, Qilong, Sivakumar, Vidyashankar, Wu, Zhiwei Steven
Several important families of computational and statistical results in machine learning and randomized algorithms rely on uniform bounds on quadratic forms of random vectors or matrices. Such results include the Johnson-Lindenstrauss (J-L) Lemma, the Restricted Isometry Property (RIP), randomized sketching algorithms, and approximate linear algebra. The existing results critically depend on statistical independence, e.g., independent entries for random vectors, independent rows for random matrices, etc., which prevent their usage in dependent or adaptive modeling settings. In this paper, we show that such independence is in fact not needed for such results which continue to hold under fairly general dependence structures. In particular, we present uniform bounds on random quadratic forms of stochastic processes which are conditionally independent and sub-Gaussian given another (latent) process. Our setup allows general dependencies of the stochastic process on the history of the latent process and the latent process to be influenced by realizations of the stochastic process. The results are thus applicable to adaptive modeling settings and also allows for sequential design of random vectors and matrices. We also discuss stochastic process based forms of J-L, RIP, and sketching, to illustrate the generality of the results.
The Best Prime Day Tech Deals: PM Edition
We've only posted one sale on the Instax SP-2 when we saw it briefly drop during the holiday season, so while this isn't a huge drop, it's a nice savings that you can use on more film. The Fujifilm INSTAX SHARE SP-2 Smart Phone Printer is an also great pick in our guide to the best instant camera. "If you want to keep shooting with your smartphone but like the idea and look of an old-school, tangible print, the Fujifilm Instax Share SP-2 is the best instant printer available," Erin Lodi wrote. "You can easily connect your phone to the printer via Wi-Fi and share access to your library of images with the free Instax Share app, which you can then use to do some minor editing and add a filter or a custom border. Press the print button, and the SP-2's high-resolution 320 dpi print is ready in just 10 seconds."