Why does my GUI take forever every time I try to plot using values retrieved from edit boxes?

I currently have a script that is meant to plot a function and it works perfectly well when it is run on its own and values for certain variables are hard coded in. I want to make a GUI to run this program so the user can define certain characteristics of the function by giving it some of the variables values by using edit boxes. When I run the program, every other aspect of the GUI works perfectly until I try to plot. At this point the GUI takes an incredibly long time to plot the values.

I have tested the plot function in the GUI by hard coding in the variable values and this works very quickly (the plot shows up almost instantly), it is only when I use a get function to define these variables that I have the problem. I use get functions a lot in the rest of the GUI and they work fine/quickly, so I do not know why this is the causing problems when I try to use it in conjunction with the plot function. There are a considerable number of data points (about 3500000) and I am trying to let the user define 5 variables which might be why it is taking so long, but again, when the variable are hard coded in, the GUI is able to graph all 3500000 data points almost instantly.

Any ideas on how to make this code run faster?

[Adam]

You need to show us the code in question, otherwise it would be pure guessing.

[Kelly Babitz]

This is run as a callback to a pushbutton.

Thanks in advance for your help!

handles = guihandles(figure);  
  timeIncrement = .0001;        
  times = (0:timeIncrement:350);

    peakTimeA = str2double(get(handles.peakTimeImpulse1,'String'));     

    widthA = str2double(get(handles.widthImpulse1,'String'));           

    concLeftVentA = normpdf(times,peakTimeA,widthA)+.0005; 

    secondImpulseCheck = get(handles.secondImpulseCB,'Value');      

    if secondImpulseCheck                                          

    peakTimeB = str2double(get(handles.peakTimeImpulse2,'String'));
    widthB = str2double(get(handles.widthImpulse2,'String'));
    heightMultiple = str2double(get(handles.heightMultImpulse2,'String'));
    concLeftVentB = heightMultiple*normpdf(times,peakTimeB,widthB)+.0005;
    else                                                                    %if its not checked, then there is no part b to the function
        concLeftVentB = 0;
    end
    concLeftVent = concLeftVentA + concLeftVentB;

concMyo = zeros(1,length(times));
  for t = 2:length(times)         
      if t < 150/timeIncrement     
          k1 = str2double(get(handles.k1Impulse1,'String'));
          k2 = str2double(get(handles.k2Impulse1,'String'));
      else
          k1 = str2double(get(handles.k1Impulse2,'String'));
          k2 = str2double(get(handles.k2Impulse2,'String'));
      end
      added = concLeftVent(t)*timeIncrement*k1;
      out = k2.*concMyo(t-1);
      concMyo(t) = concMyo(t-1) + added - out;
  end

    plot(times,concLeftVent,times,concMyo);

Answer 1

[Adam]

I would suggest using

doc profile

on this to see where the main time is being spent.

My guess would be this though:

if t < 150/timeIncrement     
   k1 = str2double(get(handles.k1Impulse1,'String'));
   k2 = str2double(get(handles.k2Impulse1,'String'));
else
   k1 = str2double(get(handles.k1Impulse2,'String'));
   k2 = str2double(get(handles.k2Impulse2,'String'));
end

You are doing that in a very long loop. You should query the edit boxes outside the loop. Calling str2double 14 million times will take a while!

Just get the two alternatives from the UI before the loop and then use whichever is needed.

You may be able to vectorise the whole loop, but certainly moving the UI access outside will be a big improvement.

[Kelly Babitz]

Thank you so much, this made it much faster!