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: cubic_is_flat.m
    path of file: ./repos/gptoolbox/mesh
    
    the code of the file until where you have to start completion: function flag = cubic_is_flat(C,tol)
  % CUBIC_IS_FLAT "Piecewise Linear Approximation of BÃ©zier Curves" [Fischer
  % 2000]
  %
  % flag = cubic_is_flat(C,tol)
  %
  % Inputs:
  %   C  4 by dim list of control points
  %   tol  tolerance
  % Outputs:
  %   flag  whether cubic is effectively flat
  %
  % See also: cubic_eval

  %assert(size(C,2) == 2);
  %ux = (3.0*C(2,1) - 2.0*C(1,1) - C(4,1)).^2;
  %uy = (3.0*C(2,2) - 2.0*C(1,2) - C(4,2)).^2;
  %vx = (3.0*C(3,1) - 2.0*C(4,1) - C(1,1)).^2;
  %vy = (3.0*C(3,2) - 2.0*C(4,2) - C(1,2)).^2;
  %ux(ux < vx) = vx(ux < vx);
  %uy(uy < vy) = vy(uy < vy);

    
function flag = cubic_is_flat(C,tol)
  % CUBIC_IS_FLAT "Piecewise Linear Approximation of BÃ©zier Curves" [Fischer
  % 2000]
  %
  % flag = cubic_is_flat(C,tol)
  %
  % Inputs:
  %   C  4 by dim list of control points
  %   tol  tolerance
  % Outputs:
  %   flag  whether cubic is effectively flat
  %
  % See also: cubic_eval

  %assert(size(C,2) == 2);
  %ux = (3.0*C(2,1) - 2.0*C(1,1) - C(4,1)).^2;
  %uy = (3.0*C(2,2) - 2.0*C(1,2) - C(4,2)).^2;
  %vx = (3.0*C(3,1) - 2.0*C(4,1) - C(1,1)).^2;
  %vy = (3.0*C(3,2) - 2.0*C(4,2) - C(1,2)).^2;
  %ux(ux < vx) = vx(ux < vx);
  %uy(uy < vy) = vy(uy < vy);
  %tolerance = 16*tol^2;
  %flag = (ux+uy) <= tolerance;

  u = (3.0*C(2,:) - 2.0*C(1,:) - C(4,:)).^2;
  v = (3.0*C(3,:) - 2.0*C(4,:) - C(1,:)).^2;
  u = max(u,v);
  % Not sure if this 16 makes sense for dim>2
  tolerance = 16*tol^2;
  flag = sum(u,2) <= tolerance;
end