CODEWITHSUNDEEP
matlabplot
user3856486
user3856486

Reputation: 547

Continuous plot while plotting inside a loop in MATLAB

I am trying to plot variables dynamically in MATLAB. I have an array (set of states) that needs to be plotted with time. I tried plot(time,theta), where theta is a 1*5 array. With this command, I get an error saying that theta should be a scalar because time is a scalar. I then tried using for-loop to plot(time,theta(i)). The problem with this is that I get data points at discrete time intervals on my plot. However I need a continuous plot. I wonder how this can be done.

Upvotes: 0

Views: 1810

Answers (2)

Zep
Zep

Reputation: 1576

Let's see if I get this straight. Time is updated at every step, and theta are five different variables that also get updated. This should work for you:

% Use your own time variable
time = 1:100;

figure;    hold on;
h = cell(5,1);    % Handles of animated lines
colors = 'rgbkm'; % Colors of lines
for t = time
   theta = randn(5,1);
   if isempty(h{1})
       % Initialize plot
       for k = 1 : 5
           h{k} = animatedline(t , theta(k) , 'LineStyle' , '-' , 'Color' , colors(k));
       end
   else
       % Update plot with new data
       for k = 1 : 5
           addpoints(h{k}, t , theta(k));
       end
   end

   % Update plot
   drawnow
end

The object animatedline was introduced in R2014b. You can still do something similar with a conventional plot and updating the XData and YData properties of the lines at each loop.

Upvotes: 0

10a
10a

Reputation: 429

You need to use hold on when plotting.

For example:

time = 1;
theta = [1:100];
figure

for i=1:100

    plot(time, theta(i),'r.')
    hold on  %--> Keeps the previous data in your plot
    time = time + 1;

end

Upvotes: 1

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