App Designer and external function

Im having issues with running my app. The m file alone works but, when I attempt to convert it to the app, its throwing errors just in the app. My code involves matrixes and vectors. Error is at the external function ElementofFasteners, I have commented the lines for a visual representation of what I am seeing. Like I said, this works as a standalone m. file without the app. What am I missing and are the app.inputs creating different variables or... need a bit of help

Error using /

Matrix dimensions must agree.

Error in Fasteners (line 29)

c1=(((t1 + t2)/(2*D))^a);

% Button pushed function: SolveButton
        function SolveButtonPushed(app, event)
            %Solve Everything here
            app.FastF1.Value = numfast(app.nf); % numfast external function-works 
            app.FastF2.Value = app.E1;
            app.FastF3.Value = app.d3;
            
            app.nnel = 3 * app.nf;
            app.nnode = 2 + (2 * app.nf);
            app.sdof = app.nnode * app.ndof;
            
            kk=zeros(app.sdof,app.sdof);    
            index=zeros(app.nel*app.ndof,1);  %orange underline (use Plate(app.,..
            for iel=1:app.nnel           
                
                if iel <= (app.nnel - app.nf)
                    [k]=Plate(app.E1,app.w,app.t1,app.L); % Plate external function-orange underline (use Plate(app.,.. 
                    index = ElementdofPlate(iel,app.nel,app.ndof,app.nf);
                else
                    if app.count == 1
                        d = app.d2;
                        app.count = app.count + 1;
                    elseif app.count == 2
                        d = app.d3;
                        app.count = app.count + 1;
                    elseif app.count == 3
                        d = app.d4;
                        app.count = app.count + 1;
                    elseif app.count == 3
                        d = app.d5;
                        app.count = app.count + 1;
                    elseif app.count == 4
                        d = app.d6;
                        app.count = app.count + 1;
                    else
                        d = app.d1;
                        app.count = app.count + 1;
                    end
                    [k]=Fasteners(app.E1,app.E2,app.E3,app.t1,app.t2,d); % Fastners external function-orange underline (use Fasteners(app.,.. 
                    index = ElementdofFasteners(iel,app.nf); %  external function-orange underline (use Elemt..(app.,.. 
                end
                
                kk=Assemble(kk,k,index); % external function-orange underline (use Elemt..(app.,.. 
            end
            %
            % Applying the Boundary conditions
            [kk] = constraints(kk,1) ;%  external function-orange underline (use Elemt..(app.,.. 
            [kk] = KRED(kk,app.nnode);%  external function-orange underline (use Elemt..(app.,.. 
            [uu] = Displacements(kk,app.P,app.nnode); %  external function-orange underline (use Elemt..(app.,.. 
            app.FastF4.Value = uu(1);
            

Answer 1

[darkphotonix]

Check the order of the callbacks

Answer 2

[Cris LaPierre]

You do not call a function named ElementofFasteners in the code you have shared.

The error message suggests to me the problem is that your inputs in the app are different from what they are when you call the function in MATLAB. Since we have no information on what they should be, I'd suggest starting to debug by using breakpoints and comparing the inputs in the app to what you expect them to be.

I'd suggest paying close attention to the dimensions. It might be that the function was designed for the inputs to be column vectors, but in the app they are created as a row vectors.

[darkphotonix]

It's called 11 lines from the bottom "ElementdofFasteners", typo.

the Index variable is a 1 x 2.... [value1 value2]

all that is needed is for ElementdofFasterners is two integers

Isn't iel an integer and app.nf an integer as well.

  % Value changed function: NumberofDropDown
        function NumberofDropDownValueChanged(app, event)
            temp_nf = app.NumberofDropDown.Value;
            app.nf= str2num(temp_nf);
        end

[Cris LaPierre]

Ah, sorry. I searched for it but it obviously didn't find this.

iel is an integer, but I don't know what app.nf is.

What is the calling syntax of ElementdofFasteners? Can you share the function declaration line? Do you perhaps need to pass the inputs in as a 1x2 vector? If so, enclose the inputs in square brackets.

index = ElementdofFasteners([iel,app.nf]);

[darkphotonix]

I figured it out, it was actually quite simple. I forgot matlab reads line by line even with the functions and the solve button was before the the variable input for app.nf, thus nf never existed. After, reordering the callbacks it worked out nicely!

Thanks for your help Cris.