Department of Mathematics;
University of Florida;
Gainesville 118105;
USA;
Industrial and Systems Engineering;
University of Florida;
Gainesville 118105;
USA;
Corresponding author.Department of Mathematics;
Hangzhou Dianzi University;
Hangzhou 310018;
China;
Constrained nonconvex and nonsmooth optimization; Smooth approximation; Proximal gradient algorithm with extrapolation; Gradient descent algorithm; Image reconstruction;