TY - UNPB M1 - working_paper N2 - This paper proposes two proximal Newton-CG methods for convex nonsmooth optimization problems in composite form. The algorithms are based on a a reformulation of the original nonsmooth problem as the unconstrained minimization of a continuously differentiable function, namely the forward-backward envelope (FBE). The first algorithm is based on a standard line search strategy, whereas the second one combines the global efficiency estimates of the corresponding first-order methods, while achieving fast asymptotic convergence rates. Furthermore, they are computationally attractive since each Newton iteration requires the approximate solution of a linear system of usually small dimension. PB - ArXiv A1 - Patrinos, Panagiotis A1 - Stella, Lorenzo A1 - Bemporad, Alberto UR - http://arxiv.org/abs/1402.6655 Y1 - 2014/// TI - Forward-backward truncated Newton methods for convex composite optimization AV - none EP - 39 N1 - A preliminary version of this paper [1] was presented at the 52nd IEEE Conference on Decision and Control, Florence, Italy, December 11, 2013. ID - eprints2225 ER -