Subscript indices must either be real positive integers or logicals. how can i change? thanks!

dt = 0.1; % time step size in seconds

i0 = 0; % potential at time 0

Vs = 10; % positive time independant source potential

L = 2; % inductor

R = 1; % resistor

N = 10; % number of time steps

i(0) = v0; %initial condition

for loop=1:N %recursive

i(loop) = i(loop-1) + Vs*dt*/L - i(loop-1)*R/L;

end

plot([0:N-1]*dt,v, ‘-k’)

xlabel( ‘Time in seconds’)

ylabel( ‘Inductor current’)

grid on hold time = [0:N-1]*dt;

i_ana = Vs/R*(1- exp(-time*(R/L));

plot(time,I_ana,’–k’)

hold

legend( ‘Numerical solution’, ‘Analytical solution’)

Subscript indices must either be real positive integers or logicals.

Answer 1

[Bjorn Gustavsson]

Matlab uses 1-based indexing to vectors, so your line:

i(0) = v0; %initial condition

Has to be changed to:

i(1) = v0; %initial condition

Then you have to adapt the rest of your script to account for that.

HTH

Answer 2

[Andrei Bobrov]

ii(1) = v0; %initial condition
for loop=2:N %recursive
    ii(loop) = ii(loop-1) + Vs*dt*/L - ii(loop-1)*R/L;
end