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: lcfun.m
    path of file: ./repos/MuRAT/Utilities_Matlab/regtu
    
    the code of the file until where you have to start completion: function g = lcfun(lambda,s,beta,xi,fifth)

% Auxiliary routine for l_corner; computes the NEGATIVE of the curvature.
% Note: lambda may be a vector.  PCH, DTU Compute, Jan. 31, 2015.

% Initialization.

    
function g = lcfun(lambda,s,beta,xi,fifth)

% Auxiliary routine for l_corner; computes the NEGATIVE of the curvature.
% Note: lambda may be a vector.  PCH, DTU Compute, Jan. 31, 2015.

% Initialization.
phi = zeros(size(lambda)); dphi = phi; psi = phi; dpsi = phi;
eta = phi; rho = phi;
if length(beta) > length(s)  % A possible least squares residual.
    LS = true;
    rhoLS2 = beta(end