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: groupmatrix_SLEP.m
    path of file: ./repos/CS_MoCo_LAB/reconstruction/matlab/CS_LAB_matlab/utils/utils_Proximal
    
    the code of the file until where you have to start completion: function [ D, DT, ind, nodesize, waveS_l1, waveS_l12, waveS_SLEP] = groupmatrix_SLEP(n1,n2,wavelevel,waveletname_l1,waveletname_l12)
% creates the vectors and matrices needed for x=altra( v, n, ind, nodes) from SLEP package

    
function [ D, DT, ind, nodesize, waveS_l1, waveS_l12, waveS_SLEP] = groupmatrix_SLEP(n1,n2,wavelevel,waveletname_l1,waveletname_l12)
% creates the vectors and matrices needed for x=altra( v, n, ind, nodes) from SLEP package
% D: vector with indices according to a depth-first-search(tree)
% DT: inverse mapping of the wavelet coeffs
% ind: matrix with groupindices and weights
%
% (c) Marc Fischer, Thomas Kuestner
% ---------------------------------------------------------------------

if wavelevel > 4
    wavelevel = 4; % max used wavelevel for SLEP
end