How to pause running program from GUI and assign new variable value?

for example I have simple program

for x=1:1000;

y=a*x+b*x^2;

end

I want to stop at any number of x and assign new values for a and b. How can I do it from GUI?

regard

Ali

Answer 1

[Walter Roberson]

You cannot pause a running program. The closest you can get is to put in a breakpoint or a conditional breakpoint before you start running the program.

But possibly you meant something else by "from GUI"; above I was answering about the MATLAB interface to run and debug programs.

If you are constructing a GUI that is starting a routine in a callback, then there is no mechanism in MATLAB to force that routine to pause when the user clicks something (or uses the keyboard.) It is possible, however, to write the routine so that it asks whether the user would like it to pause, or so that it notices that the user has changed values in a user interface and use the new values. To do this, the routine needs to use drawnow() to give the user interface an opportunity to do pending actions, and the routine needs to get() values from the handles in order to receive the updated values. For example,

for x = 1 : 1000
 drawnow()
 a = str2double(get(handles.editbox_a, 'String'));
 b = str2double(get(handles.editbox_b, 'String'));
 y(x) = a * x + b * x^2;
end

[Husni]

Perhaps my sentence is not really correct. What I want to really do is that it has an option, if the user press it the running program is paused and then User can enter new variable

[Walter Roberson]

handles.pausebutton = uicontrol('Style', 'radio', 'Value', 0);

for x = 1 : 1000
  drawnow()
  needpause = get(handles.pausebutton, 'Value');
  if needpause
    a = input('new a?');
    b = input('new b?');
    set(handles.pausebutton, 'Value', 0)
  end
  y(x) = a * x + b * x^2;
end

[Husni]

many thanks walter...it's really helpful