Title
An algorithm for quadratic ℓ1-regularized optimization with a flexible active-set strategy.
Abstract
We present an active-set method for minimizing an objective that is the sum of a convex quadratic and <inline-formula><inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink=\"goms_a_1028062_ilm0001.gif\"/</inline-formula> regularization term. Unlike two-phase methods that combine a first-order active set identification step and a subspace phase consisting of a cycle of conjugate gradient CG iterations, the method presented here has the flexibility of computing a first-order proximal gradient step or a subspace CG step at each iteration. The decision of which type of step to perform is based on the relative magnitudes of some scaled components of the minimum norm subgradient of the objective function. The paper establishes global rates of convergence, as well as work complexity estimates for two variants of our approach, which we call the interleaved iterative soft-thresholding algorithm ISTA–CG method. Numerical results illustrating the behaviour of the method on a variety of test problems are presented.
Year
DOI
Venue
2015
10.1080/10556788.2015.1028062
Optimization Methods and Software
Keywords
DocType
Volume
convex optimization,active-set method,nonlinear optimization,lasso
Journal
30
Issue
ISSN
Citations 
6
1055-6788
6
PageRank 
References 
Authors
0.48
14
3
Name
Order
Citations
PageRank
Stefan Solntsev160.48
Jorge Nocedal23276301.50
Richard H. Byrd32234227.38