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From: Duvinage MAtthieu on 18 Mar 2010 07:06
Hi,

I would like to integrate a ODE system. However, although the script below works well when I use a function sin(wt), I don't know how to use an external function which is the result of an experiment. How can we handle with this problem ?

%principal script Here input signal is only an example but I want to replace this function by a result of an experiment.

Fe=1000; %frequence d'échantillonnage
time=500; %nombre de secondes
tspan=0:1/Fe:time;
p=[8; 1; 3];
x0=[1; 0; 5];
input_signal=sin(10*tspan);
[t,x]=ode45('adaptative_frequency_oscillators',tspan,x0,[],p,input_signal,Fe);
figure
plot(t,x(:,1))
figure
plot(t,x(:,2))
figure
plot(t,x(:,3))

%equation
function xprime = aptative_frequency_oscillators(t,x,flag,p,input_signal2,Fe);
gamma=p(1);
mu=p(2);
e=p(3);
xprime = zeros(3,1);
xprime(1)=gamma*(mu-(x(1)^2+x(2)^2))*x(1) -x(3)*x(2) +e*input_signal;
xprime(2)=gamma*(mu-(x(1)^2+x(2)^2))*x(2)+x(3)*x(1);
xprime(3)=-e*sin(10*t)*x(2)/sqrt(x(1)^2+x(2)^2);

Thank you in advance.

Matthieu
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