How do I plot N arrays at the same time as a animation?

I want to know the best way to animate several arrays into one plot, at the same time.

The example I'm working on is a closed box of balls, where I already have the arrays created. However the animation becomes very bad and choppy when there's more than one ball in animation, so I wanted to know if there's a better way of writing the code, or a more effiecent way to animate the arrays.

for i = 1:N_max
    
    for j = 1:n

        ball(j) = plot(x(j,i+1),y(j,i+1),'ok','MarkerFaceColor','k');
        set(ball,'MarkerSize',diameter)   
        
        pause(1e-3)
      
        if i~=N_max
            reset(ball(j))
        end    
      
    end    
end

Answer 1

[Star Strider]

I am not certain what you want to do. There are several functions to produce animated plots in MATLAB. One such is drawnow, some related ones are refreshdata, and there are others.

Example —

[Xs,Ys,Zs] = sphere;

figure
for k1 = 1:0.03:3.2
    Xp = Xs + cos(k1*2*pi);
    Yp = Ys + sin(k1*2*pi);
    surf(Xp, Yp, Zs)
    axis equal
    axis([-3  3    -3  3    -3  3])
    text(-2.1, -1.8, 'Revolving Sphere')
%     view(0,90)
    grid on
    refreshdata
    drawnow update
end
hold off

This does not directly address the particle animation in your Question (since I cannot run your code), however it shows what is possible.

[David]

Okey, I didn't want to add to much code to my question, but maybe it is necessary. So this is the code I have now (which still lacks on many fronts I my add).

As you can now see, at least for me, the plot is quite bad with n > 1.

%%
clc; clear all; close all; 

dt = 1e-2; 
N_max = 500;
n = 3;
diameter = 7; %Markersize

x = zeros(1,N_max);
y = zeros(1,N_max);
vx = zeros(1,N_max);
vy = zeros(1,N_max);

for i = 1:n
    
    % Initial values
    x0(i,1) = randi([-2000,2000])/1000; % gives value between -2 and 2
    y0(i,1) = randi([-2000,2000])/1000; 
    vx0(i,1) = randi([-5000,5000])/1000;
    vy0(i,1) = randi([-5000,5000])/1000; 

    x(i,1) = x0(i,1);
    vx(i,1) = vx0(i,1);  
    y(i,1) = y0(i,1);
    vy(i,1) = vy0(i,1); 

end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Plot the box
figure;hold on; 
square_length = 2;
axis([-square_length square_length -square_length square_length])
axis off
axis square

cornersX = [-square_length, square_length];
cornersY = [-square_length square_length]; 

for j = 1:2
    
plot([cornersX(j),cornersX(j)],[cornersY(1),cornersY(2)],'-k'); % | |
plot([cornersX(1),cornersX(2)],[cornersY(j),cornersY(j)],'-k'); % _ _

end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Define the corners
corner = [square_length-1e-3, square_length-1e-3]; 

for j = 1:n

    for i=1:N_max

        x(j,i+1) = x(j,i) + vx(j,i)*dt; 
        y(j,i+1) = y(j,i) + vy(j,i)*dt; 

        vx(j,i+1) = vx(j,i); 
        vy(j,i+1) = vy(j,i);

        position = [x(j,i+1),y(j,i+1)];


        if norm(position) >= norm([corner(1),corner(2)])-dt % if it hits a corner
             vy(j,i+1) = -vy(j,i); 
             vx(j,i+1) = -vx(j,i);

        elseif abs(y(j,i+1)) >= square_length - dt % if it hits horizontal wall
            vy(j,i+1) = -vy(j,i);

        elseif abs(x(j,i+1)) >= square_length - dt % if it hits vertical wall
            vx(j,i+1) = -vx(j,i);

        end
    

    end

end


% Time for plot

for i = 1:N_max
    
    for j = 1:n

        ball(j) = plot(x(j,i+1),y(j,i+1),'ok','MarkerFaceColor','k');
        set(ball,'MarkerSize',diameter)   
        
        pause(1e-3)
      
      if i~=N_max
          reset(ball(j))
      end
      
    end
      
end