How to get 2-variable function from a GUI textbox?

Hey

I need to input a 2 variable function like f(x,y) and give x and y lower and upper limit and use numerical methods on it. I did it for 1 variable function(find a GUI) but now there are problems with f(x) turnning into f(x,y) and fevel(fx,x) that cannot be (fx,x,y).

here is .m file and the problem area:

x1 = str2double(get(handles.editx1,'String'));

x2 = str2double(get(handles.editx2,'String'));

fx = vectorize(inline(get(handles.editfunc,'String')));

x = [x1:0.001:x2];

values = feval(fx,x);

maxi=max(values);

mini=(min(values));

if mini > 0

      mini = 0;

end;

method = get(handles.pop_int,'Value');

Answer 1

[Walter Roberson]

Why not? feval() accepts multiple arguments. And you don't need feval() anyhow for this purpose.

I recommend that you stop using inline() and start using str2func()

fx = str2func(['@(x,y)' vectorize(get(handles.editfunc,'String'))]);

values = fx(x, y);

I suspect you will also be wanting to use ndgrid() to construct the arguments you pass to your function.

[Peter weber]

Thank you sir I went to build a simple GUI ,very simple to see if this is work but another problem came on...

>> Example Error: File: Example.m Line: 225 Column: 4 The function "textresult_CreateFcn" was closed with an 'end', but at least one other function definition was not. To avoid confusion when using nested functions, it is illegal to use both conventions in the same file. I did add an "end" at the end of file....malab itself said so...

[Walter Roberson]

Remove the last 'end' from textresult_CreateFcn

[Peter weber]

Thanks again but I have another Questions If I may: I want to use I = trapz(y,trapz(x,F,2)) with the above fx=fx(x,y) but it doesn't work... 2. remember that function you mentioned above fx(x,y), how can I change for instance "x" into " a*x+b" or even entirely something else like 5*t-9...greatly thankful in advance