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_test_dhog.m
    path of file: ./repos/Image-Harmonization-Dataset-iHarmony4/Lalonde and Efros/utilsPrivate/3rd_party/vlfeat-0.9.14/toolbox/test
    
    the code of the file until where you have to start completion: function vl_test_dhog
% VL_TEST_DHOG Test VL_DHOG function
%   For a correctness test, see TEST_DHOG_INTER.

% Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
% All rights reserved.
%
% This file is part of the VLFeat library and is made available under
% the terms of the BSD license (see the COPYING file).

tri = 3 ;
I = single(vl_test_pattern(2))  ;

    
function vl_test_dhog
% VL_TEST_DHOG Test VL_DHOG function
%   For a correctness test, see TEST_DHOG_INTER.

% Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
% All rights reserved.
%
% This file is part of the VLFeat library and is made available under
% the terms of the BSD license (see the COPYING file).

tri = 3 ;
I = single(vl_test_pattern(2))  ;
n = 1 ;

for siz=1:5
  for step=1:10
    ben(n).size = siz ;
    ben(n).step = step ;
    tic ;
    for t=1:tri
      [f_,d_] = vl_dhog(I,'step', step, 'size', siz) ;
    end