function LuFactGUI(keyword,varargin)
global A B X
if nargin == 0
   
H = findobj(0,'Tag','LuFact_figp');
if ~isempty(H)
   warning('Another PROGRAM is running.  Only 1 PROGRAM can be run at a time.');
   figure(H);
   return
end

LuFactGUI_figp = figure('units','normalized','pos',[0.30 0.30 0.40 .30],'menu','none', ...
              'tag','LuFactGUI_figp',...
              'Color',get(0,'DefaultUIControlBackgroundColor'), ...
              'DefaultUIControlUnit','norm');
         
figure(LuFactGUI_figp); 
str='列主元分解法的通用程序';
set(gcf,'name',str,'numbertitle','off');
set(gca,'Visible','off');
set(gcf,'defaultuicontrolfontsize',11);
uicontrol('pos',[0.40 0.72 0.25 .12],'string','讀入系數(shù)矩陣', ...
   'CallBack','LuFactGUI(''ReadA'')');

uicontrol('pos',[0.40 0.52 0.25 .12],'string','讀入右端向量', ...
   'CallBack','LuFactGUI(''ReadB'')');

uicontrol('pos',[0.10 .72 0.25 .12],'string','編輯系數(shù)矩陣', ...
   'CallBack','LuFactGUI(''EditA'')');

uicontrol('pos',[0.10 0.52 0.25 .12],'string','編輯右端向量', ...
   'CallBack','LuFactGUI(''EditB'')');

uicontrol('pos',[0.10 0.32 0.25 .12],'string','計(jì)算', ...
   'CallBack','LuFactGUI(''cal'')');

uicontrol('pos',[0.40 0.32 0.25 .12],'string','查看結(jié)果', ...
   'CallBack','LuFactGUI(''result'')'); 

uicontrol('pos',[0.10 0.12 0.25 .12],'string','Help', ...
   'CallBack','LuFactGUI(''Help'')');

uicontrol('pos',[0.40 0.12 0.25 .12],'string','作者信息', ...
   'CallBack','LuFactGUI(''Info'')');

uicontrol('pos',[0.70 0.12 0.25 .12],'string','關(guān)閉', ...
   'CallBack','LuFactGUI(''close'')');
else
    
switch keyword

case 'EditA'
   fid=fopen('CoeMatrix.txt','a+');
   open('CoeMatrix.txt');
 %%%%%%%%%%%%%%%%%%%%%%%%%%
case 'EditB'
    fid=fopen('MatrixB.txt','a+');
    open('MatrixB.txt');
   
 %%%%%%%%%%%%%%%%%%%%%%%%%% 
 
 case 'ReadA'
[filename,pathname]=uigetfile('.txt','打開系數(shù)矩陣數(shù)據(jù)文件');
filepath=strcat(pathname,filename);
if ~isempty(filepath)
A=load(filepath);
else 
    msgbox('打開文件失敗','對(duì)話框','warn');
end
 %%%%%%%%%%%%%%%%%%%%%%%%%%
 
 case 'ReadB'
[filename,pathname]=uigetfile('.txt','打開右端向量數(shù)據(jù)文件');
filepath=strcat(pathname,filename);
if ~isempty(filepath)
B=load(filepath);
else 
    msgbox('打開文件失敗','對(duì)話框','warn');
end

 %%%%%%%%%%%%%%%%%%%%%%%%%% 
 case 'cal'
if ~isempty(A)&&~isempty(B)
 X=LuFact(A,B);
 msgbox({'計(jì)算完畢','點(diǎn)擊【查看結(jié)果】按鈕查看結(jié)果'},'對(duì)話框','help');
else 
    msgbox('請(qǐng)先讀入系數(shù)矩陣和右端向量數(shù)據(jù)','對(duì)話框','warn');
end

%%%%%%%%%%%%%%%%%%%%%%%%%% 
 case 'result'
    msgbox({'X=',['(',num2str(X'),')']},'解向量X','help');
    
%%%%%%%%%%%%%%%%%%%%%%%%%%
case 'Help'
   msgbox({['  解n階線性方程組Ax=B的列主元三角分解法通用程序  '],...
          ['* 編輯數(shù)據(jù)文件時(shí)，請(qǐng)嚴(yán)格按矩陣行和列順序輸入數(shù)值，'], ...
          ['  同一行元素用空格符號(hào)隔開'], ...
          ['* 請(qǐng)勿輸入其余多余的字符'], ...
          ['* 確保A是 n×n 階矩陣'], ...
          ['* 確保B是 n×1 階矩陣'],...
          },'幫助','help');

%%%%%%%%%%%%%%%%%%%%%%%%%%
case 'Info'
   msgbox({['作者：羅云標(biāo)'],...
          ['單位：土木工程學(xué)院'], ...
          ['學(xué)號(hào)：050593'], ...
          ['Email：lyb-039@163.com'], ...
          ['水平有限，程序簡(jiǎn)陋'], ...
          ['不足之處，敬請(qǐng)?jiān)?#039;]
          },'作者信息','help');   
      
 %%%%%%%%%%%%%%%%%%%%%%%%%%     
case 'close'
    close;
end % switch statement for callbacks
end     % end of NewtonMethod

% % 子函數(shù)
function X=LuFact(A,B);
[N,N]=size(A);
X=zeros(N,1);
Y=zeros(N,1);
C=zeros(1,N);
R=1:N;
for P=1:N-1
    [max1,j]=max(abs(A(P:N,P)));
    C=A(P,:);
    A(P,:)=A(j+P-1,:);
    A(j+P-1,:)=C;
    d=R(P);
    R(P)=R(j+P-1);
    R(j+P-1)=d;
    if A(P,P)==0
        disp('系數(shù)矩陣 A 奇異 ，沒有獨(dú)立解');
        break
    end
    for k=P+1:N
        mult=A(k,P)/A(P,P);
        A(k,P)=mult;
        A(k,P+1:N)=A(k,P+1:N)-mult*A(P,P+1:N);
    end
end
    Y(1)=B(R(1));
    for k=2:N
        Y(k)=B(R(k))-A(k,1:k-1)*Y(1:k-1);
    end
    X(N)=Y(N)/A(N,N);
    for k=N-1:-1:1
        X(k)=(Y(k)-A(k,k+1:N)*X(k+1:N))/A(k,k);
    end