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: GRID_LinearProgrammingSmoothing_rx0_volume.m
    path of file: ./repos/tracacode/1911-COAWST/script/mfiles/LP_Bathymetry/Mfiles
    
    the code of the file until where you have to start completion: function NewBathy=GRID_LinearProgrammingSmoothing_rx0_volume(...

    
function NewBathy=GRID_LinearProgrammingSmoothing_rx0_volume(...
    MSK, Hobs, rx0max, AreaMatrix)
% GRID_LinearProgrammingSmoothing_rx0_volume(MSK, Hobs, rx0max, AreaMatrix)
%
% ---MSK(eta_rho,xi_rho) is the mask of the grid
%      1 for sea
%      0 for land
% ---Hobs(eta_rho,xi_rho) is the raw depth of the grid
% ---rx0max is the target rx0 roughness factor
% ---AreaMatrix(eta_rho,xi_rho) is the matrix of grid cells areas.
[eta_rho, xi_rho]=size(MSK);
tol=0.0001;
Ksea=find(MSK == 1);
if (min(Hobs(Ksea)) < tol)
  disp('The bathymetry should always be positive');
  error('Please correct');
end