for loop

[wildany]

Dear All,

I want to create FOR LOOP by Matlab to solve this equation :

x(t+dt)=(dt*A+I)*x(t)+B*dt

in which

A =[0 1;-6 -5]
I=eye(2)
B=[0;1]
dt=0.01

initial condition

x(0)=[0;0]
x(t) = vector 2x1

Any one can give me some ideas ?

I have created some scripts in m file as per below :

ft=1; % Step Input
dt=0.01; % Time Interval (can be changed)
t_end=5; % End of Time for plotting (fix)
Nstep=round(t_end/dt);
Xo=zeros(2,1); % Initial Condition for X, at t=0
Xdot0=A*Xo+B*ft; % Intitial Condition for Xdot, at t=0
Y=C*Xdot0; % Intitial Condition for Y, at t=0
I=eye(size(A)); % Identity Matrix
for i=1:Nstep
x(i)= Xo
x(i+1)=(dt*A+I)*x(i)+B*dt;
end

However, It does not work

Thanks a lot
Wildany

 

[GregLocock]

What does

Y=C*Xdot0; % Intitial Condition for Y, at t=0

accomplish?



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[wildany]

Hi Greg,


Please neglect Y=C*Xdot0 and Xdot0=A*Xo+B*ft

the problem is only inside the 'for loop'.

Thanks a lot
Wildany

 

[GregLocock]

Well, there is certainly a problem in there, and I found the error message remarkably informative. It tells me which line the first error is on and what the problem is.

Personally I think you have got the algorithm completely wrong, but I don't play guessing games with bits of code.





Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[IRstuff]

Could it possibly that you're setting x(i) to zero at each iteration?

Is this for school? Student postings are not allowed.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!