Index exceeds the number of array elements. Index must not exceed 1.

1 view (last 30 days)
I'm trying to apply runge kutta method to my problem but i messed up the code at line34(k1_ivme) and matlab giving this error. What should i do for fix this?
z(1)=-314;
v(1)=0;
h=0.1;
tson=10;
t=0:h:tson;
L=1.5;
vi=0.000001;
n = 100;
for i=1:n-1;
Re(i)=abs(v(i))*L/vi;
Cf(i)=0.075/((log(Re)-2).^2);
k1_hiz(i)=h*v(i);
k1_ivme=h*(5207.3-3.47*Cf(i)*v(i)^2);
k2_hiz(i)=h*(v(i)+0.5*k1_ivme(i));
k2_ivme(i)=h*(5207.3-3.47*(Cf(i)+0.5*k1_ivme)*(v(i)+0.5*k1_ivme))^2;
k3_hiz(i)=h*(v(i)+0.5*k2_ivme(i));
k3_ivme(i)=h*(5207.3-3.47*(Cf(i)+0.5*k2_ivme)*(v(i)+0.5*k2_ivme))^2;
k4_hiz(i)=h*(v(i)+k3_ivme(i));
k4_ivme(i)=h*(5207.3-3.47*(Cf(i)+k3_ivme)*(v(i)+k3_ivme))^2;
z(i+1)=z(i)+(1/6*(k1_hiz(i)+2*k2_hiz(i)+2*k3_hiz(i)+k4_hiz(i)));
v(i+1)=v(i)+(1/6*(k1_ivme(i)+2*k2_ivme(i)+2*k3_ivme(i)+k4_ivme(i)));
end

Answers (1)

Torsten
Torsten on 17 Jan 2022
z(1)=-314;
v(1)=0;
h=0.1;
tson=10;
t=0:h:tson;
L=1.5;
vi=0.000001;
n = 100;
for i=1:n
Re(i)=abs(v(i))*L/vi;
Cf(i)=0.075/((log(Re(i))-2).^2);
k1_hiz(i)=h*v(i);
k1_ivme(i)=h*(5207.3-3.47*Cf(i)*v(i)^2);
k2_hiz(i)=h*(v(i)+0.5*k1_ivme(i));
k2_ivme(i)=h*(5207.3-3.47*(Cf(i)+0.5*k1_ivme(i))*(v(i)+0.5*k1_ivme(i)))^2;
k3_hiz(i)=h*(v(i)+0.5*k2_ivme(i));
k3_ivme(i)=h*(5207.3-3.47*(Cf(i)+0.5*k2_ivme(i))*(v(i)+0.5*k2_ivme(i)))^2;
k4_hiz(i)=h*(v(i)+k3_ivme(i));
k4_ivme(i)=h*(5207.3-3.47*(Cf(i)+k3_ivme(i))*(v(i)+k3_ivme(i)))^2;
z(i+1)=z(i)+(1/6*(k1_hiz(i)+2*k2_hiz(i)+2*k3_hiz(i)+k4_hiz(i)));
v(i+1)=v(i)+(1/6*(k1_ivme(i)+2*k2_ivme(i)+2*k3_ivme(i)+k4_ivme(i)));
end
Now the code runs, but there must be something wrong with your RK4 integrator.

Categories

Find more on Introduction to Installation and Licensing in Help Center and File Exchange

Products


Release

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!