i am not getting chaotic plot because of warning

1 view (last 30 days)
function dx = compactchua(t,x)
dx=zeros(4,1);
dx(1) = -(1/(8200*47*1e-9))*x(2);
dx(2) = (((x(3)-x(2))/2000) -(x(4).^3*4.7e3+1e3))/6.8e-9;
dx(3) = ((x(2)-x(3))/2000 - x(4))/68e-9;
dx(4) = (x(3))/(22*10^-9);
end
[t,x] = ode15s(@compactchua,[0 5e-7],[0 12.24e-3 12.24e-3 1.7]);
plot(x(:,2),x(:,3));
error
Warning: Failure at t=6.943264e-08. Unable to meet integration tolerances without reducing the step size below
the smallest value allowed (2.117582e-22) at time t.
>>
  2 Comments
David Goodmanson
David Goodmanson on 16 Feb 2022
Hi nune,
you might want to double check the equations, especially the signs, because the solution gives the impression of wanting to increase without bound.

Sign in to comment.

Answers (1)

Bhavana Ravirala
Bhavana Ravirala on 16 Feb 2022
Hi Pratyusha,
In case of sharp discontinuities in the reference input, it is possible that this warning is generated at intermediate time steps. As it tries to reduce the time step to a small amount in order to counter the abrupt change due to the discontinuity in the reference input.
For sharp discontinuities, it might not be possible to avoid this warning. However, for non-discontinuous inputs we can set relative and absolute tolerance to a higher number than the default setting.
For more information refer the below links:
Hope this helps.

Categories

Find more on Exponents and Logarithms 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!