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: linearCompressibility.m
    path of file: ./repos/mtex/TensorAnalysis/@complianceTensor
    
    the code of the file until where you have to start completion: function beta = linearCompressibility(S,x)
% computes the linear compressibility of an elasticity tensor
%
% Description
%
% $$\beta(x) = S_{ijkk} x_i x_j$$
%
% Input
%  S - elastic @complianceTensor

    
function beta = linearCompressibility(S,x)
% computes the linear compressibility of an elasticity tensor
%
% Description
%
% $$\beta(x) = S_{ijkk} x_i x_j$$
%
% Input
%  S - elastic @complianceTensor
%  x - list of @vector3d
%
% Output
%  beta - linear compressibility in directions v
%

% return a function if required
if nargin == 1 || isempty(x)
  beta = S2FunHarmonicSym.quadrature(@(x) linearCompressibility(S,x),'bandwidth',2,S.CS);
  return
end