Events with ODE45 to change output values

Hi

I am integrating an ode system describing number of individual dynamics. Unfortunatly I have values asymptotically close to 0 and <1 that is not realistic and it should be 0.

Do you know how to use the events function when the variables reach 1, then considere this variable = 0 but NOT stop the ode integration?

The idea would be to do the same than:

ballode

but with only one integration bu not with loops and integrating many times when you have reached the threashold ...

Many thanks,

D.

[darova]

What is wrong with loops?

n = 200;
f = @(u) [u(2) -9.8];                   % diff equation
ts = linspace(0,3,n)';
dt = ts(2)-ts(1);                       % timestep
u = ones(n,2);
for i = 1:n-1
    u(i+1,:) = u(i,:) + dt*f(u(i,:));
    if u(i+1,1) < 0                     % if ball reaches y = 0
        u(i+1,:) = -0.8*u(i+1,:);       % decrease energy and change the sign
    end
end
plot(ts,u(:,1))
axis equal

[David Demory]

Thanks darova for your answer. However, ballode was just an exemple. In my case I want to replace by 0 a variable when it < 1 in the ode45 integration and not stoping the integration.

[darova]

I think it's impossible. I can't help :(