Fast/Finite Fourier Transform

http://www.scholarpedia.org/article/FitzHugh-Nagumo_model

I want to do a 'fft' of the first two equations in the article. I managed to put them into a first order function.

function dot=fitz(t,v);

dot=zeros(2,1);

dot(2)=0.08*(v(1)+0.7-0.8*v(2));

dot(1)=v(1)-(v(1)^3)/3-v(2);

%%%%I have also managed to solve by plotting it with ode45.

[t,v]=ode45('fitz',[0 200],[0,0]);

plot(t,v(:,2),t,v(:,1));

plot(t,v)

%%%But how would I be able to do a Fourier analysis of the two non linear ODE's?

%%%An example would also help me understand it.

Answer 1

[Walter Roberson]

I think you want a non-equispaced FFT, NFFT; see http://www.cims.nyu.edu/cmcl/nufft/nufft.html

The "t" would be the time points and the "v" would be the values.