how to save outputs of a loop in vectors to use later ??? urgent please help

iam making a loop to calculate some values for theta from 0:360 but i cant plot correctly it always plots for me the last point out from the loop and i want to print the values corresponding the theta in the loop for my project and plot it here is the code

    l1=0;%input('input l1: ');
    l2=3;%input('input l2: ');
    l3=8;%input('input l3: ');
    w2=20.9;%;input('input w2: ');
    for i=0:360
        a=i*(pi/180);
        b=l2*sin(a);
        c=l2*cos(a);
        d=-(asin((l1+a)/l3));
        th3=d*(180/pi)*i;
        e=l2*sin(d);
        f=l2*cos(d);
        g=l3*sin(d);
        h=l3*cos(d);
        l4=c+f;
        w3=-w2*(c/f);
        v4=-w2*(b)-w3*(g);
        alp3=(b*(w2^2)+g*(w3^2))/h;
        a4=[-(g*(alp3)+c*(w2^2)+h*(w3^2))];
        plot (i,a4)

    end

here i want to plot a4,th2 but plots only one point and i want to the 360 values of the a4? but how

thanks in advance

Answer 1

[Matt Fig]

I don't see a th2. Assuming you meant one point per loop iteration...

l1=0;%input('input l1: ');
l2=3;%input('input l2: ');
l3=8;%input('input l3: ');
w2=20.9;%;input('input w2: ');
a4 = zeros(1,361);
for ii=0:360
    a = ii*(pi/180);
    b = l2*sin(a);
    c = l2*cos(a);
    d = -(asin((l1+a)/l3));
    th3 = d*(180/pi)*i;
    e = l2*sin(d);
    f = l2*cos(d);
    g = l3*sin(d);
    h = l3*cos(d);
    l4 = c+f;
    w3 = -w2*(c/f);
    v4 = -w2*(b)-w3*(g);
    alp3 = (b*(w2^2)+g*(w3^2))/h;
    a4(ii+1) = -(g*(alp3)+c*(w2^2)+h*(w3^2));
end

plot(0:360,a4)

[bassam imam]

sorry i meant plot (i,a4);

and how can i see a4 as a vector to use later in some operation else?

[bassam imam]

really thank u very much............really appreciate it

[Matt Fig]

To see a4, simply type:

a4

at the end of the loop. This will dump the vector to the screen.

[bassam imam]

worked fine thanks allot :D

Answer 2

[Ahmad]

Hi, Where is th2. Anyways, I do not know what is this meant to do but try this :

      th3_vect=zeros(0);
      a4_vect=zeros(0);
        for i=0:36
          a=i*(pi/180);
          b=l2*sin(a);
          c=l2*cos(a);
          d=-(asin((l1+a)/l3));
          th3=d*(180/pi)*i;

          e=l2*sin(d);
          f=l2*cos(d);
          g=l3*sin(d);
          h=l3*cos(d);
          l4=c+f;
          w3=-w2*(c/f);
          v4=-w2*(b)-w3*(g);
          alp3=(b*(w2^2)+g*(w3^2))/h;
          a4=[-(g*(alp3)+c*(w2^2)+h*(w3^2))];
          th3_vect(length(th3_vect)+1)=th3;
          a4_vect(length(a4_vect)+1)=a4;
      end
         plot (th3_vect,a4_vect)

[Matt Fig]

I would not recommend growing arrays in the loop like this. The effect is to slow the code down. For such a small final length this may not matter a whole lot, but for larger lengths this will really slow things down...

[Ahmad]

I would completely go for the answer Mr. Matt Fig Suggested.

Thanks for your help Sir.

[bassam imam]

thanks for your help Mr. Matt fig and Mr.Ahmad

finished my kinematics project at last :D and plotted all figures required thanks agian:D