plotting for every single loop

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)

Answer 1

[Walter Roberson]

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.

[Ali Roshanzamir]

Thank you very much for your clear answer. I have one more question.

Is it possible to plot the loop for v=1 + v=2 + v=3 and ....?

[Walter Roberson]

Yes. If you look more carefully at your code,

for v=1:2:30
    x=x+(0.085*N/pi)*sin(v*teta)/v;
    y((v+1)/2,:)=x;
end
plot(teta,x)

You are plotting x, not y. So you do not need to record y: you could simplify the code to

for v=1:2:30
    x=x+(0.085*N/pi)*sin(v*teta)/v;
end
plot(teta,x)

and then change to

for v=1:30

The indexing at a non-integer stops being a problem if you stop indexing that way ;-)

[Ali Roshanzamir]

Yes, I see. thank you so much.