MATLAB: Plotting for every single loop

for loopplotting

Hi everyone.

I got this code and I have a question about it. Is it work for every single "v"? like 1, 2 ,3 ,4 …….

If not how can I make it for every "v" ?

N=45;
teta=0:0.02:5*pi;
y=zeros(10,length(teta));
x=zeros(size(teta));
for v=1:2:30
    x=x+(0.085*N/pi)*sin(v*teta)/v;
    y((v+1)/2,:)=x;
end
plot(teta,x)

Best Answer

for v=1:2:30

means that the loop should execute for 1, 1+2, 1+2+2, 1+2+2+2, 1+2+2+2+2 and so on -- which is to say, 1, 3, 5, 7, 9, and so on.

y((v+1)/2,:)=x;

Because your v values are presently odd integers, then v+1 becomes the next even integer, and /2 will be an integer. So y(1) then y(2), y(3) and so on will be assigned to.

If you were to switch to

for v=1:30

then you would be including even v such as 2, and (2+1)/2 would not be an integer, and you would not be able to use (v+1)/2 as a subscript.

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MATLAB: How to save “y” and “dy” in the same vector A each time the loop WHILE is incremented

It actually is not clearing them. Think of ‘A’ as a deck of cards. Here, ‘A(:,:,1)’ is the first card, ‘A(:,:,2)’ is the second card, and so for the rest. All the values are still there.

Experiment with preallocating a new matrix ‘Ae’ and then concatenating to it in each loop to see if that works better for you:

Ae = [];
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MATLAB: Help with Elastic Collision

You need to be careful about pre and post collision velocities, and the boundary checks:

t=0;
dt=0.5;
x1=1;
y1=0;
v1x=0;
v1y=0;
m1=1;
% centers = [x1, y1];
x2=-8;
y2=0;
v2x=2;
v2y=0;
m2=1;
% centers2 = [x2, y2];
% t=0, plot position of particles
subplot (3, 1, 1)
plot ([-10, 10], [-10, 10], 'w')
% obj1 = viscircles(centers,1)
% obj2 = viscircles (centers2, 1)
r1 = rectangle ('Position', [x1,y1,1,1], 'FaceColor', 'r', 'Curvature', [1,1]);
r2 = rectangle ('Position', [x2,y2,1,1], 'FaceColor', 'b', 'Curvature', [1,1]);
axis ([-10 10 -10 10]);
subplot (3, 1, 2)
plot (t, x1)
plot (t, x2)
xlabel ('Time')
ylabel ('Position-X')
subplot (3, 1, 3)
plot  (t, y1)
plot  (t, y2)
xlabel ('Time')
ylabel ('Position-Y')
xx1 = [ ];
xx2 = [ ];
yy1 = [ ];
yy2 = [ ];
% Start moving :)
while t < 100
    % Update "old" values
    v1xold = v1x; v2xold = v2x; v1yold = v1y; v2yold = v2y;
    
    if 1 < sqrt((x2-x1)^2+(y2-y1)^2)
        x1 =  x1 + (v1x * dt);
        x2 =  x2 + (v2x * dt);  
        y1 =  y1 + (v1y * dt);
        y2 = y2 + (v2y * dt);
        xx1 = [xx1, x1];
        xx2 = [xx2, x2];
        yy1 = [yy1, y1];
        yy2 = [yy2, y2];
       
    else   % Use "old" values on RHS
        v1x = ((m1-m2)/(m1+m2))*v1xold + ((2*m2)/(m1+m2)) * v2xold; 
        v1y = ((m1-m2)/(m1+m2))*v1yold + ((2*m2)/(m1+m2)) * v2yold;
        
        v2x = ((m2-m1)/(m1+m2))*v2xold + ((2*m1)/(m1+m2)) * v1xold;
        v2y = ((m2-m1)/(m1+m2))*v2yold + ((2*m1)/(m1+m2)) * v1yold;
        x1 =  x1 + (v1x * dt);
        x2 =  x2 + (v2x * dt);  
    
        y1 =  y1 + (v1y * dt);
        y2 =  y2 + (v2y * dt);
        
        
        xx1 = [xx1, x1];
        xx2 = [xx2, x2];
        yy1 = [yy1, y1];
        yy2 = [yy2, y2];
    end
    % At Boundary - Turn Direction
            if x1+dt*v1x>9
                v1x= -v1x;
            end
            if x2+dt*v2x>9
                v2x=-v2x;
            end
            if x1+dt*v1x<-10
                v1x=abs(v1x);
            end
            if x2+dt*v2x<-10
                v2x=abs(v2x);
            end
            if y1+dt*v1y>9
                v1y=-v1y;
            end
            if y2+dt*v2y>9
                v2y=-v2y;
            end
            if y1+dt*v1y<-10
                v1y=abs(v1y);
            end
            if y2+dt*v2y<-10
                v2y=abs(v2y);
            end
            
 
    %update the position of the rectangles 
    set(r1,'Position', [x1,y1,1,1]);
    set(r2,'Position', [x2,y2,1,1]);
    
    subplot (3, 1, 2)
    plot (t, x1,'ro',t,x2,'bs')
    axis([0 100 -10 10])
    xlabel ('Time')
    ylabel ('Position-X')
    
    subplot (3, 1, 3)
    plot (t, y1,'ro',t,y2,'bs')
    axis([0 100 -10 10])
    xlabel ('Time')
    ylabel ('Position-Y')
    drawnow
      t= t+ dt;
 end

Best Answer

Related Solutions

MATLAB: How to save “y” and “dy” in the same vector A each time the loop WHILE is incremented

MATLAB: Help with Elastic Collision

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