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: vl_demo_kdtree_sift.m
    path of file: ./repos/2016_person_re-ID/vlfeat/toolbox/demo
    
    the code of the file until where you have to start completion: function vl_demo_kdtree_sift

    
function vl_demo_kdtree_sift
% VL_DEMO_KDTREE_SIFT
%   Demonstrates the use of a kd-tree forest to match SIFT
%   features. If FLANN is present, this function runs a comparison
%   against it.

% AUTORIGHS

rand('state',0) ;
randn('state',0);

do_median = 0 ;
do_mean = 1 ;

% try to setup flann
if ~exist('flann_search', 'file')
  if exist(fullfile(vl_root, 'opt', 'flann', 'build', 'matlab'))
    addpath(fullfile(vl_root, 'opt', 'flann', 'build', 'matlab')) ;
  end
end
do_flann = exist('nearest_neighbors') == 3 ;
if ~do_flann
  warning('FLANN not found. Comparison disabled.') ;
end