Is this the correct syntax for replacing a specific element in a dependent vector?

numElem = 9990;
w = linspace(2*pi,2*pi*10^18,numElem);
wRes = 2*pi*10^9;

for n = 1:numElem
    if w(n) > wRes 
        w = [w(1:n), wRes, w(n:numElem)];
    end
end

freq = w ./ (2*pi);
lambda =  299792458 ./ freq;

if w == wRes
    B = 2*pi./lambda;
else
    B = pi/2 .*w./wRes;
end

I am trying to create a range of w's and make sure that a specific value, wRes is in there. For that specific wRes, I want an exceptional value for B. Is the above code the correct way of going about it?

Answer 1

[Walter Roberson]

Note that if you are trying to replace values > wRes with wRes, then another way of doing that is:

w = min(w, wRes);

[Real Name]

I figured it out, my code was really bad. I had meant to insert wRes into a sorted vector and keep the order.

Answer 2

[Brendan Hamm]

It looks like you are trying to change any values of w which are greater than wRes to be wRes instead, but you are instead placing an additional element into w at the (n+1)th position and then at the next iteration checking if that value is greater than wRes. I think what you are looking for is logical indexing.

idx = w > wRes;

The ith index of idx is true (1) if w(i) > wRes. Now you can use this to access the elements of w where idx is true and change only those values:

w(idx) = wRes;

Consider this on a simpler example:

x = 1:10;
idx = x > 5; % 6th through 10th elements are true!
x(idx) = -1; % 6th through 10th elements are now -1!

[Real Name]

No, it's B that I wanted to change.