The non-convex $α\|\cdot\|_{\ell_1}-β\| \cdot\|_{\ell_2}$ $(α\geβ\geq0)$ regularization has attracted attention in the field of sparse recovery. One way to obtain a minimizer of this regularization is the ST-($α\ell_1-β\ell_2$) algorithm which is similar to the classical iterative soft thresholding algorithm (ISTA). It is known that ISTA converges quite slowly, and a faster alternative to ISTA is the projected gradient (PG) method. However, the conventional PG method is limited to the classical $\ell_1$ sparsity regularization. In this paper, we present two accelerated alternatives to the ST-($α\ell_1-β\ell_2$) algorithm by extending the PG method to the non-convex $α\ell_1-β\ell_2$ sparsity regularization. Moreover, we discuss a strategy to determine the radius $R$ of the $\ell_1$-ball constraint by Morozov's discrepancy principle. Numerical results are reported to illustrate the efficiency of the proposed approach.
On the interplay of basis smoothness and specific range conditions occurring in sparsity regularization
Chemnitz University of Technology(开姆尼茨工业大学);Johannes Kepler University(约翰·开普勒大学);Industrial Mathematics Institute(工业数学研究所);Johann Radon Institute for Computational and Appied Mathematics(约翰·拉顿计算与应用数学研究所)
A modified projected walk on spheres method for elliptic equations on high-dimensional embedded manifolds: algorithm and error estimates
School of Mathematics, Shanghai University of Finance and Economics(上海财经大学数学学院);School of Mathematics and Statistics, Hainan University(海南大学数学与统计学院);Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences(中国科学院数学与系统科学研究院计算数学与科学工程计算研究所)
Beyond convergence rates: Exact recovery with Tikhonov regularization with sparsity constraints
TU Braunschweig, Institute for Analysis and Algebra(布伦瑞克工业大学,分析与代数研究所);Zentrum für Technomathematik, Universität Bremen, Fachbereich Mathematik/Informatik(不来梅大学,技术与数学中心,数学/信息学系)