Faster way to update a plot?

Hello dear community.

I have the following problem:

My program creates a two different arrays (vectors of different lengths) in each step of a for-loop. Right now I am plotting these two vectors within the loop which makes it update each time the loop is completed. Unfortunately the plotting seems to have a great impact on the speed of my program. I would like to ask for advice to speed up my loop.

Thank you for your help!

Answer 1

[Chad Greene]

Do you need to plot inside the loop? The best thing you can do is wait on plotting until after the loop. For example,

hold on 
for x = 1:1000 
   plot(x,sind(x),'bo')
end

will take much longer than

x = 1:1000; 
y = NaN(size(x)); 
for k = 1:length(x); 
   y(k) = sind(x(k)); 
end 
plot(x,y,'bo')

If you can remove the loop entirely, that will be fastest:

x = 1:1000; 
y = sind(x); 
plot(x,y,'bo')

Experiment with the above. Put tic before a section and toc after to see how long it takes your computer to run a given section.