function bandem(action);
//BANDEM1 Banana function minimization demonstration.
//   This demonstration shows the minimization         
//   of Rosenbrocks "banana function":                
//                                                           
//       f(x)= 100*(x(2)-x(1)^2)^2+(1-x(1))^2          
//                                                            
//   It is called the banana function because of       
//   the way the curvature bends around the            
//   origin. It is notorious in optimization examples  
//   because of the slow convergence which             
//   most methods exhibit when trying to solve         
//   this problem.                                     
//                                                            
//   This function has a unique minimum at the         
//   point x=[1, 1] where f(x)=0. We show here         
//   a number of techniques for its minimization       
//   starting at the point x=[-1.2, 1].                
//                                                            
//   File name: bandem1.m                            

//   Adapted for Expo by Ned Gulley, 6-21-93
//   Copyright (c) 1990-98 by The MathWorks, Inc.
//   $Revision: 5.10 $  $Date: 1998/07/24 19:53:59 $

if nargin<1,
   action='initialize';
end;

if strcmp(action,'initialize'),
   figNumber=figure( ...
      'Name','Using the Optimization Toolbox', ...
      'NumberTitle','off', ...
      'Visible','off');
   axes( ...
      'Units','normalized', ...
      'Visible','off', ...
      'Position',[0.05 0.40 0.70 0.75]);
   
   //===================================
   // Set up the Comment Window
   top=0.35;
   left=0.05;
   right=0.75;
   bottom=0.05;
   labelHt=0.05;
   spacing=0.005;
   promptStr=str2mat(' ',...
      ' Press the buttons at the right to see examples of', ...
      ' Optimization Toolbox commands using medium-scale algorithms.');
   // First, the MiniCommand Window frame
   frmBorder=0.02;
   frmPos=[left-frmBorder bottom-frmBorder ...
         (right-left)+2*frmBorder (top-bottom)+2*frmBorder];
   uicontrol( ...
      'Style','frame', ...
      'Units','normalized', ...
      'Position',frmPos, ...
      'BackgroundColor',[0.5 0.5 0.5]);
   // Then the text label
   labelPos=[left top-labelHt (right-left) labelHt];
   uicontrol( ...
      'Style','text', ...
      'Units','normalized', ...
      'Position',labelPos, ...
      'BackgroundColor',[0.5 0.5 0.5], ...
      'ForegroundColor',[1 1 1], ...
      'String','Comment Window');
   // Then the editable text field
   txtPos=[left bottom (right-left) top-bottom-labelHt-spacing];
   txtHndl=uicontrol( ...
      'Style','edit', ...
      'HorizontalAlignment','left', ...
      'Units','normalized', ...
      'Max',10, ...
      'BackgroundColor',[1 1 1], ...
      'Position',txtPos, ...
      'Callback','bandem1(''eval'')', ...
      'String',promptStr);
   // Save this handle for future use
   set(gcf,'UserData',txtHndl);
   
   //====================================
   // Information for all buttons
   labelColor=[0.8 0.8 0.8];
   top=0.95;
   left=0.80;
   btnWid=0.15;
   btnHt=0.08;
   // Spacing between the button and the next command's label
   spacing=0.02;
   
   //====================================
   // The CONSOLE frame
   frmBorder=0.02;
   yPos=0.05-frmBorder;
   frmPos=[left-frmBorder yPos btnWid+2*frmBorder 0.9+2*frmBorder];
   uicontrol( ...
      'Style','frame', ...
      'Units','normalized', ...
      'Position',frmPos, ...
      'BackgroundColor',[0.5 0.5 0.5]);
   
   //====================================
   // The BFGS button
   btnNumber=1;
   yPos=top-(btnNumber-1)*(btnHt+spacing);
   labelStr='BFGS';
   callbackStr='bandem1(''demobutton'')';
   
   // Generic popup button information
   btnPos=[left yPos-btnHt btnWid btnHt];
   uicontrol( ...
      'Style','pushbutton', ...
      'Units','normalized', ...
      'Position',btnPos, ...
      'String',labelStr, ...
      'Callback',callbackStr, ...
      'UserData',btnNumber);
   
   //====================================
   // The DFP button
   btnNumber=2;
   yPos=top-(btnNumber-1)*(btnHt+spacing);
   labelStr='DFP';
   callbackStr='bandem1(''demobutton'')';
   
   // Generic popup button information
   btnPos=[left yPos-btnHt btnWid btnHt];
   uicontrol( ...
      'Style','pushbutton', ...
      'Units','normalized', ...
      'Position',btnPos, ...
      'String',labelStr, ...
      'Callback',callbackStr, ...
      'UserData',btnNumber);
   
   //====================================
   // The STEEPEST DESCENT button
   btnNumber=3;
   yPos=top-(btnNumber-1)*(btnHt+spacing);
   labelStr='Steepest';
   callbackStr='bandem1(''demobutton'')';
   
   // Generic popup button information
   btnPos=[left yPos-btnHt btnWid btnHt];
   uicontrol( ...
      'Style','pushbutton', ...
      'Units','normalized', ...
      'Position',btnPos, ...
      'String',labelStr, ...
      'Callback',callbackStr, ...
      'UserData',btnNumber);
   
   //====================================
   // The SIMPLEX button
   btnNumber=4;
   yPos=top-(btnNumber-1)*(btnHt+spacing);
   labelStr='Simplex';
   callbackStr='bandem1(''demobutton'')';
   
   // Generic popup button information
   btnPos=[left yPos-btnHt btnWid btnHt];
   uicontrol( ...
      'Style','pushbutton', ...
      'Units','normalized', ...
      'Position',btnPos, ...
      'String',labelStr, ...
      'Callback',callbackStr, ...
      'UserData',btnNumber);
   
   //====================================
   // The GAUSS-NEWTON button
   btnNumber=5;
   yPos=top-(btnNumber-1)*(btnHt+spacing);
   labelStr='G-N';
   callbackStr='bandem1(''demobutton'')';
   
   // Generic popup button information
   btnPos=[left yPos-btnHt btnWid btnHt];
   uicontrol( ...
      'Style','pushbutton', ...
      'Units','normalized', ...
      'Position',btnPos, ...
      'String',labelStr, ...
      'Callback',callbackStr, ...
      'UserData',btnNumber);
   
   //====================================
   // The LEVENBERG-MARQUARDT button
   btnNumber=6;
   yPos=top-(btnNumber-1)*(btnHt+spacing);
   labelStr='L-M';
   callbackStr='bandem1(''demobutton'')';
   
   // Generic popup button information
   btnPos=[left yPos-btnHt btnWid btnHt];
   uicontrol( ...
      'Style','pushbutton', ...
      'Units','normalized', ...
      'Position',btnPos, ...
      'String',labelStr, ...
      'Callback',callbackStr, ...
      'UserData',btnNumber);
   
   //====================================
   // The INFO button
   uicontrol( ...
      'Style','push', ...
      'Units','normalized', ...
      'Position',[left bottom+btnHt+spacing btnWid btnHt], ...
      'String','Info', ...
      'Callback','bandem1(''info'')');
   
   //====================================
   // The CLOSE button
   uicontrol( ...
      'Style','push', ...
      'Units','normalized', ...
      'Position',[left bottom btnWid btnHt], ...
      'String','Close', ...
      'Callback','close(gcf)');
   
   // Now uncover the figure
   set(figNumber,'Visible','on');
   
elseif strcmp(action,'demobutton'),
   method=get(gco,'UserData');
   txtHndl=get(gcf,'UserData');
   
   // Plotting the banana function
   cla reset;
   axis off;
   x=-2:.2:2;
   y=-1:.2:3;
   [xx,yy]=meshgrid(x,y);
   zz=100*(yy-xx.^2).^2+(1-xx).^2;
   // Set up the appropriate colormap
   // In this case, the colormap has been chosen to give the surf plot
   // a nice healthy banana color.
   hsv2=hsv;
   hsv3=[hsv2(11:64,:); hsv2(1:10,:)];
   // draw the surf plot
   surfHndl=surface(x,y,zz,'EdgeColor',[.8 .8 .8]);
   axis off;
   view(10,55);
   colormap(hsv3);
   hold on;
   [c,contHndl]=contour3(x,y,zz+50,[100 500],'k');
   set(contHndl,'Color',[.8 .8 .8]);
   drawnow
   plot3(-1.2,1,267.62,'ko', ...
      'MarkerSize',15, ...
      'LineWidth',2, ...
      'EraseMode','none');
   text(-1.2,1.2,267.62,'   Begin', ...
      'Color',[0 0 0], ...
      'EraseMode','none');
   plot3(1,1,0,'ko', ...
      'MarkerSize',15, ...
      'LineWidth',2, ...
      'EraseMode','none');
   text(0.8,1.4,0,'   End', ...
      'Color',[0 0 0], ...
      'EraseMode','none');
   x=[-1.2 1];
   // Uncomment the next line for random initial conditions
   //x=[4*rand-2 4*rand-1];
   
   OPTIONS=optimset('LargeScale','off');
   // if you want cubic interpolation line search, set OPTIONS(7)=1
   // otherwise mixed polynomial line search is used.
   // 
   //OPTIONS(7)=1;
   // Turn off all messages, even if no convergence.
   OPTIONS = optimset(OPTIONS,'display','off');
   if method==1,
      str= ...
         [' Broyden-Fletcher-Goldfarb-Shanno         '  
         ' (Unconstrained quasi-Newton minimization)'];
      set(txtHndl,'String',str);
      GRAD='[100*(4*x(1)^3-4*x(1)*x(2))+2*x(1)-2; 100*(2*x(2)-2*x(1)^2); xpbanplt(x)]';
      f='100*(x(2)-x(1)^2)^2+(1-x(1))^2';
      OPTIONS = optimset(OPTIONS,'gradobj','on','MaxFunEvals',200);
      str2='[x,fval,exitflag,output] = fminunc({f,GRAD},x,OPTIONS);';
      [x,fval,exitflag,output] = fminunc({f,GRAD},x,OPTIONS);
      
   elseif method==2,
      str= ...
         [' Davidon-Fletcher-Powell                   '  
         ' (Unconstrained quasi-Newton minimization) '];
      set(txtHndl,'String',str);
      OPTIONS = optimset(OPTIONS,'HessUpdate','dfp','gradobj','on','MaxFunEvals',200);
      GRAD='[100*(4*x(1)^3-4*x(1)*x(2))+2*x(1)-2; 100*(2*x(2)-2*x(1)^2); xpbanplt(x)]';
      f='100*(x(2)-x(1)^2)^2+(1-x(1))^2';
      str2='[x,fval,exitflag,output] = fminunc({f,GRAD},x,OPTIONS);';
      [x,fval,exitflag,output] = fminunc({f,GRAD},x,OPTIONS);
      
   elseif method==3,
      str= ...
         [' Steepest Descent                '  
         ' (Unconstrained minimization)    '];
      set(txtHndl,'String',str);
      OPTIONS = optimset(OPTIONS,'HessUpdate','steepdesc','gradobj','on','MaxFunEvals',300);
      GRAD='[100*(4*x(1)^3-4*x(1)*x(2))+2*x(1)-2; 100*(2*x(2)-2*x(1)^2); xpbanplt(x)]';
      f='100*(x(2)-x(1)^2)^2+(1-x(1))^2';
      str2='[x,fval,exitflag,output] = fminunc({f,GRAD},x,OPTIONS);';
      [x,fval,exitflag,output] = fminunc({f,GRAD},x,OPTIONS);
      
   elseif method==4,
      str= ...
         [' Nelder-Mead                         '  
         ' (Unconstrained simplex minimization)'];
      set(txtHndl,'String',str);
      OPTIONS = optimset(OPTIONS,'MaxFunEvals',200);
      f='[100*(x(2)-x(1)^2)^2+(1-x(1))^2; xpbanplt(x)]';
      str2='[x,fval,exitflag,output] = fminsearch(f,x,OPTIONS);';
      [x,fval,exitflag,output] = fminsearch(f,x,OPTIONS);
      
   elseif method==5,
      str= ...
         [' Gauss-Newton                '  
         ' (Least squares minimization)'];
      set(txtHndl,'String',str);
      OPTIONS = optimset(OPTIONS,'LevenbergMarq','off','MaxFunEvals',200,'Jacobian','on');
      JAC='[-20*x(1), 10; -1, 0; xpbanplt(x)]';
      f='[10*(x(2)-x(1)^2),(1-x(1))]';
      str2='[x,resnorm,residual,exitflag,output]= lsqnonlin({f,JAC},x,[],[],OPTIONS);';
      [x,resnorm,residual,exitflag,output]= lsqnonlin({f,JAC},x,[],[],OPTIONS);
      fval = resnorm;
      
   elseif method==6,
      str= ...
         [' Levenberg-Marquardt          '  
         ' (Least squares minimization) '];
      set(txtHndl,'String',str);
      OPTIONS = optimset(OPTIONS,'LevenbergMarq','on','MaxFunEvals',200,'Jacobian','on');
      JAC='[-20*x(1), 10; -1, 0; xpbanplt(x)]';
      f='[10*(x(2)-x(1)^2),(1-x(1))]';
      str2='[x,resnorm,residual,exitflag,output]= lsqnonlin({f,JAC},x,[],[],OPTIONS);';
      [x,resnorm,residual,exitflag,output]= lsqnonlin({f,JAC},x,[],[],OPTIONS);
      fval = resnorm;
      
   end;
   funEvals=sprintf(' Number of iterations: //g.  Number of function evaluations: //g.', output.iterations, output.funcCount);
   str=get(txtHndl,'String');
   str=str2mat(str,' ',str2,' ',funEvals);
   set(txtHndl,'String',str);
   
elseif strcmp(action,'info'),
   helpwin(mfilename);
end;    // if strcmp(action, ...

endfunction
