The main issue in your code comes from how the “for” loops are structured and how variables are assigned inside them. In MATLAB, a “for” loop iterates over a vector of indices or values, and you need to preallocate your result arrays to store values at each time step. Also, the assignments to “phidot” and “phi” should be made inside the loop for each time value.
To fix this:
- Use a “for” loop to iterate over the indices of your time vector.
- Preallocate your result arrays (“phidot” and “phi”) before the loop.
- Assign values to each element of these arrays inside the loop using the current time value.
Here is the updated “for” loop code:
% Preallocate result arrays
phidot = zeros(size(t));
phi = zeros(size(t));
for i = 1:length(t)
ti = t(i);
% Determine sigma_a based on time
if ti < 2.5
sigma_a = -3;
else
sigma_a = 0;
end
% Calculate beta for this time
beta = (L_sigma_a / L_phi) * sigma_a;
% Calculate phidot and phi for this time
phidot(i) = beta * (1 - exp(lambda * ti));
phi(i) = beta * (ti - (1/tau) * exp(tau * ti));
end
For more information on “zeros” and ”for” refer to their respective links below:
