Solving second order delay differential equations

[Alexjamescooper]

Hi Zulko,

firstly, thank you for writing ddeint!. I am trying to solve an initial value problem for the case that x''(t) is known and depends on x(t-dt). In scipy without the delay I do this as following:

def function(z, t):
return np.array([x''(z[1]), z[0]])

then odeint returns an np.array of [x',x]

However in ddeint this seems difficult as I cannot index z. Any help would be appreciated.

Cheers!

[phboett]

Well more than a year later: Does the example in https://computationalmindset.com/en/mathematics/solving-delay-differential-equations-in-python-using-numerical-methods.html help?

[Menginventor]

I implemented dde solver base on ddeint with scipy.integrate.solve_ivp which is newer version.
https://github.com/Menginventor/dde_ivp
It support rk23, rk45 adaptive step size. vectorized variable, dense output, and event detection
I would be more efficient and accurate the existing ddeint. Feel free to try it out.