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: test21.m
    path of file: ./repos/SuiteSparse/CHOLMOD/MATLAB/Test
    
    the code of the file until where you have to start completion: function test21
%TEST21 test cholmod2 on diagonal or ill-conditioned matrices
% Example:
%   test21
% See also cholmod_test

% Copyright 2006-2023, Timothy A. Davis, All Rights Reserved.
% SPDX-License-Identifier: GPL-2.0+

fprintf ('=================================================================\n');
fprintf ('test21: test cholmod2 on diagonal or ill-conditioned matrices\n') ;

f = [
 72     % HB/bcsstm22
 315    % Bai/mhdb416

    
function test21
%TEST21 test cholmod2 on diagonal or ill-conditioned matrices
% Example:
%   test21
% See also cholmod_test

% Copyright 2006-2023, Timothy A. Davis, All Rights Reserved.
% SPDX-License-Identifier: GPL-2.0+

fprintf ('=================================================================\n');
fprintf ('test21: test cholmod2 on diagonal or ill-conditioned matrices\n') ;

f = [
 72     % HB/bcsstm22
 315    % Bai/mhdb416
 64     % HB/bcsstm09
 71     % HB/bcsstm21
 1207   % Oberwolfach/t2dal_e
 354    % Boeing/crystm02
 1211   % Oberwolfach/t3dl_e
 ]' ;

for i = f

    Prob = ssget (i)                                                        %#ok
    A = Prob.A ;
    n = size (A,1) ;
    x = ones (n,2) ;
    b = A*x ;
    fprintf ('nnz: %d\n', nnz (A)) ;

    x1 = A\b ;
    x2 = cholmod2 (A,b) ;

    s = norm (A,1) * norm (x,1) + norm (b,1) ;
    resid1 = norm (A*x1-b,1) / s ;
    resid2 = norm (A*x2-b,1) / s ;

    err1 = norm (x-x1,1) ;
    err2 = norm (x-x2,1) ;

    fprintf ('MATLAB  resid %6.1e err %6.1e\n', resid1, err1) ;
    fprintf ('CHOLMOD resid %6.1e err %6.1e\n', resid2, err2) ;
    fprintf ('condest %6.1e\n', condest (A)) ;

end