How to put for loop outputs into array?

I have a for loop that gives output values as the loop iterates and i am trying to put all of the outputs Q(2) into a [1 200] array. Here's what i've got so far, any help would be appreciated.

Q = zeros(1,200);
for i = 5:15/199:20
A = [-2 1 2 0 0 0; 0 0 -2 1 2 0; 0 0 0 0 -2 3; 1 1 0 0 0 0; 0 -1 1 1 0 0; 0 0 0 -1 1 1];
b = [0; 0; 0; i; 0; 0];
Q = A\b;
Q2 = Q(1);
Q2
end

Answer 1

[Stephen23]

With MATLAB it is always much simpler and more versatile to loop over indices, rather than looping over data. When you do that, then your task also becomes trivial by using indexing into the output variable. Note that:

• matrix A does not change in the loop, so should be moved byfore the loop.
• it adjusts the number of iterations automatically to the number of elements in V.

A = [-2 1,2,0,0,0;0,0,-2,1,2,0;0,0,0,0,-2,3;1,1,0,0,0,0;0,-1,1,1,0,0;0,0,0,-1,1,1];
V = 5:15/199:20;
N = numel(V);
Q = zeros(1,N); % preallocate output array!
for k = 1:N
    b = [0;0;0;V(k);0;0];
    x = A\b;
    Q(k) = x(1);
end

And checking:

>> Q(:)
ans =
    2.5294
    2.5675
    2.6057
    2.6438
    2.6819
    2.7201
    2.7582
    2.7963
    2.8345
    2.8726
    ... more rows here
    9.7745
    9.8126
    9.8507
    9.8889
    9.9270
    9.9651
   10.0033
   10.0414
   10.0795
   10.1176

[Riley Heymann]

what is the purpose of V? and what is the purpose of b?

I'm trying to copy the process but for a much smaller matrix. Could you rewrite this code for a 8x8 matrix please?