How to increase size of array

Hey guys, I have this code (below) that leads to a plot. My question is how can I increase the size of Zh so my w linspace can have more data points? Right now, it can only do 33 because Zh is a 1x33. Is there any way I can change that? I'm not too advanced in Matlab, so I'm not sure how to increase it.

w_limit = 5*2*pi;
wn = sqrt(k./m);
F_harm = 1;
w = 0;
Zh = 0;

for w = 0:w_limit
    
r = w./wn;
Ft = k*Y*(r.^2)*(sqrt((1 + ((2*z*r).^2))/(((1-(r.^2)).^2)+((2*z*r).^2))));
F_harm = [F_harm;Ft];
Z = m*(w.^2)*0.0254/sqrt(((k-(m*(w.^2))).^2)+(c*w).^2);
Zh = [Zh Z];
w = w + 0.001; 
end

w = linspace(0,5*2*pi,33);
figure(4)
plot(w,Zh)

Answer 1

[Walter Roberson]

w_limit = 5*2*pi;

5*2*pi is 10*pi which is about 31.4 .

for w = 0:w_limit

that would be 0:31.4-ish which would be 0, 1, 2, 3, ... 29, 30, 31 . That is 32 different iterations.

Zh = 0;

Zh starts out with a 0

Zh = [Zh Z];

Each of those 32 iterations, a new value is put at the end of Zh. Because Zh started with 0, the array will have 32+1 = 33 entries.

Z = m*(w.^2)*0.0254/sqrt(((k-(m*(w.^2))).^2)+(c*w).^2);

With w starting out as 0, the Z entry corresponding to w == 0 will be 0. So when Z is put on the end of the Zh that starts out as 0, the first two entries are going to end up being 0.

w = w + 0.001; 

w is your for loop variable. Each iteration of the for loop, any change you made to w at the end of the loop will be ignored, as if you had not changed w (exception: the very last change "sticks")

So the second iteration will not use w of 0.001, and the one after that will not use w of 0.002 -- you are using w = 0:w_limit and that tells it to proceed by integer steps.

If you had used

for w = 0:0.001:w_limit

then your w would change 0.001 at a time.

[Tony Vastano]

Okay I get it, thank you. I increased it a bit and the plot seems to be much more fluid, as well as the subsequent plots not shown here.