Unable to meet integration tolerances.

Recently I wrote a program about a Non-autonomous ODE system as follow

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options = odeset('RelTol',1e-4,'AbsTol',1e-4);

[t x]=ode45(@function,0:2*pi/100:400,[1e+4 500 1000],options);

function xdot=function(t,x)

xdot(1)=(1e+6)-0.02*x(1)-((3.5e-5)+(2e-5)*cos(2*pi*t))*x(1)*x(3);

xdot(2)=((3.5e-5)+(2e-5)*cos(2*pi*t))*x(1)*x(3)-(0.02+45.6)*x(2);

xdot(3)=45.6*x(2)-73.02*x(3);

xdot=xdot';

end

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However, when I run it, the Program always show error information as follows

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Warning: Failure at t=4.401339e+000. Unable to meet integration tolerances without reducing the step size below the smallest value allowed (1.421085e-014) at time t.

> In ode45 at 355 In measles2attractor at 19 Warning: Imaginary parts of complex X and/or Y arguments ignored.

> In measles2attractor at 21

I will be very appreciate if someone could tell me What is wrong and How to modify the code!

Answer 1

[Sean de Wolski]

iskeyword function

ans = 1

I'm surprised it even let you call it that way. You cannont name a function function since it's reserved for the definition of functions. Rename it to fun (both at the top of the file and the *.m file name) or something desciptive about what it does and see if the error remains.

[lan yuntian]

Thank you very much for your answer. You are very right.

In fact, when I run the the program. the name of the function is an other name.

[Sean de Wolski]

Update your question with the _actual_ function names and code to help us eliminate guesswork.