Continuous running of code

I have been trying to implement a way to allow my code to run continuously on a MATLAB graph but with no avail. I have used the drawnow function which has helped me run it in real-time but I would like for the code to run like oscilloscope. Is there a function that I am missing?

[Geoff Hayes]

Alex - please provide a sample of the code that you are using so that we can provide some guidance. Are you trying to update a figure with new data every x seconds or are you trying to do something else?

[Alex Perkins]

The following code worked well in the sense that it is updating but I have an equation in a for loop for 0.7 seconds and I have it now to update every 0.7 seconds but instead of the plot continuing from the previous one it essentially pasted the same info. Is it possible to do this?

[Geoff Hayes]

Alex - yes, it is possible to do this. You should be able to modify the below code to suit your needs.

Answer 1

[Geoff Hayes]

Alex - you could try the following which will generate a sine wave and change the last second of data on each iteration of the while loop

 figure;
 hold on;
 set(gca,'Color','k');
 set(gca,'YLim',[-2 2]);

 % generate five seconds of data with frequency f
 fs = 200;
 dt = 1/fs;
 t  = linspace(0,5-dt,5*fs);
 f  = 2;
 a  = 1;
 y  = a*sin(2*pi*t*f);

 h = plot(t,y,'Color','g');

 while true

    % generate a new second of data
    tn = linspace(max(t)+dt,max(t)+1,fs);

    % randomly change the frequency
    if rand>0.6
        fn = randi(5,1,1);
    else
        fn = f;
    end

    yn = sin(2*pi*tn*fn);

    % remove the old data and replace with the new
    t = [t(fs+1:end) tn];
    y = [y(fs+1:end) yn];

    % update the plot
    set(h,'XData',t,'YData',y);
    pause(1);

 end

Note how set is used to update the x and y data of the handle h which corresponds to plot graphics handle. Try the above and see what happens!

Answer 2

[Shubham Hokarne]

Is there any command in matlab to run the program for infinite time and update the data ?

[Walter Roberson]

No, MATLAB does not have any transfinite operations, but you might be able to find some useful information about implementation of transfinite quantities in MATLAB from https://www.maths.ox.ac.uk/system/files/attachments/PartB2015-16_web_0.pdf

I think you will find it easier to execute indefinitely, updating as you go, instead of waiting until after an infinite time has passed.

[Geoff Hayes]

Shubham - which program and which data (should be updated)? Please provide some context. And in the future, please don't post a question as an answer to a different question.