You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: algo_FCSA_SLEP_2D_real.m
    path of file: ./repos/CS_MoCo_LAB/reconstruction/matlab/CS_LAB_matlab/@Proximal
    
    the code of the file until where you have to start completion: function [imageCha, ssim_map, metrics] = algo_FCSA_SLEP_2D_real( obj,input )   
% 2D real-valued variant of FCSA
% based on Huang et al. paper on FCSA
% with Liu and Ye's idea to use the Moreau-Yosida regularization to solve the group lasso problem, using the SLEP package.
%
% input:
% obj           CS reconstruction object (holding all parameters)
% input         struct containing recon parameters and image
%
% output:
% imageCha      reconstructed channel individual image
% ssim_map      structural similarity map
% metrics       evaluation metrics 
%
% (c) Marc Fischer, Thomas Kuestner, May 2015
% -------------------------------------------------------------------------

timer_SLEP = tic;

    
function [imageCha, ssim_map, metrics] = algo_FCSA_SLEP_2D_real( obj,input )   
% 2D real-valued variant of FCSA
% based on Huang et al. paper on FCSA
% with Liu and Ye's idea to use the Moreau-Yosida regularization to solve the group lasso problem, using the SLEP package.
%
% input:
% obj           CS reconstruction object (holding all parameters)
% input         struct containing recon parameters and image
%
% output:
% imageCha      reconstructed channel individual image
% ssim_map      structural similarity map
% metrics       evaluation metrics 
%
% (c) Marc Fischer, Thomas Kuestner, May 2015
% -------------------------------------------------------------------------

timer_SLEP = tic;

%% variables:
% internal flags
flag_wavetree = true;
flag_fast = true;
flag_extend