why do I receive error "Not enough Argument"

Hello

I am writting codes to a s-function block to create demo or animate of a liquid Tank ,but I have a problem which is "not enough Arguments".I am not sure if you know what is the problem,I have paste my written codes below.

Thank you

function [sys,x0,str,ts,setPt1,setPt2,waterx1,vessel1Hndl,vessel1Ht, vesselHndlList,waterY1,vessel2Hndl,lineHndl1,lineHndl2]=vesseldemo2project (u,flag,t,x)

switch flag==4
     
    case 0
     [sys,x0,str,ts,vesseldemo2project]=mdlInitializeSizes;
      
     get(vesseldemo2project,'UserData') =vesselHndlList; 
            get( vesselHndlList(1),'YData');
           yData(1)=yOffset;
            yData(3:4)=[1 1]*u(2)+yOffset;
            set( vesselHndlList(1),'YData',yData);
            
            yData=get(x(2),'YData');
            yData([3 4])=[1 1]*u(2)+yOffset;
            set(x(2),'YData',yData);
            
            yData=[1 1]*u(1)+1;
            set(x(3),'YData',yData);      
    case 2 
  
         %Tank body details.................................
         sys=mdlUpdate(t,x,u);
         vessel1Ht=1;
        vessel1Wid=1;
        vessel1Init=0;
         setPt1=0.5;
         setPt2=0.75;
        vesselx=[0 0 1 1]-0.5;
         vesselY=[1 0 0 1];
   
    line(1.1*vesselx*vessel1Wid+1,vesselY*vessel1Ht+0.95,'LineWidth',2,'Color','black');
    
 % Draw the water..............................................
   waterx1=vesselx*vessel1Wid+1;
    waterx=vesselY*vessel1Init+1;
         x=patch(waterx,waterx,'blue','EdgeColor','none');
 
   % Draw the gray wall............................................
        waterY1([1 2 5])=vessel1Ht*[1 1 1]+1;
      waterY([3 4 ])=x*[1 1 ]+1;
    vessel2Hndl=patch(waterx,waterY,[.9 .9 .9],'EdgeColor','none');
    
 case 3
   

str = [];
ts  = [.1 0];
vessel1Wid=1;
    vessel1Ht=1;
     vessel1Init=0;
       setPt1=0.5;
       setPt2=0.75;
     vesselx=[0 0 1 1]-0.5;
  vesselY=[1 0 0 1];
   waterx1=vesselx*vessel1Wid+1;
     waterx=vesselY*vessel1Init+1;
      waterY1([1 2 5])=vessel1Ht*[1 1 1]+1;
       waterY([3 4 ])=vessel1Init*[1 1 ]+1;
        vessel1Hndl=patch(waterx,waterx,'blue','EdgeColor','none');
         vessel2Hndl=patch(waterx,waterY,[.9 .9 .9],'EdgeColor','none');
         lineHndl1=line([0 0.4],setPt1*[0.5 0.5]+1,'Color','red','LineWidth',4);
         hlod on
        lineHndl2=line([0 0.4],setPt2*[0.75 0.75]+1,'Color','red','LineWidth',4);
        hold on
       set(gcf, ... 
     'Color',[.9 .9 .9], ...
   'UserData',[vessel1Hndl vessel2Hndl lineHndl]);
   
   set(gca, ...
  'XLim',[0 2],'YLim',[0 3.5], ...
  'XColor','black','YColor','black', ...
  'Box','on');
axis equal
    
    xlabel('Water Level Control','Color','black','FontSize',10);
     set(get(gca,'XLabel'),'Visible','on');
 
   x0=0; 
  otherwise
    error(message('vesseldemo:vesseldemo2project:UnhandledFlag', flag));
    
     
 end

[Piyush Aggarwal]

"Not enough arguments" error is simply an indicative of the fact that you are calling some MATLAB/user-defined function with the wrong syntactical signature. You will need to pass correct number of inputs arguments to any function. Look closely at the exact error message you are recieving. It will tell you which line and which function is causing the trouble.

[KEYVAN PEBDANI SAHRAEI]

There is not any error in command lines but at the end I have the problem. Thank you for advicing.

Answer 1

[Walter Roberson]

Note: you are using a Level 1 S-Function inside of Simulink

https://www.mathworks.com/help/simulink/sfg/maintaining-level-1-matlab-s-functions.html

     get(vesseldemo2project,'UserData') =vesselHndlList; 

That attempts to assign a value to an array named get indexed at integer locations indicated by vesseldemo2project and the offsets calculated by converting the character vector 'UserData' into character codes. This is not at all likely to be what you want.

More likely would be

vesselHndlList = get(vesseldemo2project,'UserData');

If this is not enough to fix the problem, you will need to post more of the error message, showing which line it is complaining about.

[KEYVAN PEBDANI SAHRAEI]

Thank you for your help and advice,I have got the same problem still,There is an image below indicates the error .

Is there any useful websites ,documents and youtube video to learn how program s_function block ? I know about MATLAB documents but they are so basic.

Thanks

[Walter Roberson]

Ah, your function itself is named vesseldemo2project, so the line you had

     get(vesseldemo2project,'UserData') =vesselHndlList; 

would have attempted to call the same function you are executing except with no inputs, expecting it to return something that you could get() the UserData field from. But that fails because the function needs input arguments.

Based upon later lines, I think you should be using

 vesselHndlList = get(gcf,'UserData');

[KEYVAN PEBDANI SAHRAEI]

I have got error still which is:

Not enough input arguments.

Error in vesseldemo2project line 3.

switch flag='4'.

[Walter Roberson]

The file is intended to be called from Simulink by configuring it through an S-Function Block. If you call it at the MATLAB level, you need to pass in at least four variables (possibly 5 for that code). The four major ones are documented at the link I posted at the top of my Answer.

[KEYVAN PEBDANI SAHRAEI]

Thank you

Answer 2

[Abhisek Pradhan]

This may be a case of defining and calling the function in the same script. If this is the case try separating them out and see if it works.