Cannot Solve First Order Plus Delay Time(FOPDT)

[Agnes159]

Hi, I try to simulate FOPDT using ddeint. However, it doesn't work for me.
May I have your advice on this?

My system is as shown:

dxdt = (-x(t)+Kp*u(t-d))/taup

where Kp = 1.0 ; d = 180 ; taup = 181 
x(0) = 0.0 and u is a step change from 0 to 0.3

model = lambda x,t,d,Kp,taup : (-x(t)+Kp*u(t-d))/taup
g = lambda t : 0

tt=np.linspace(0,1440,1000)
yy=ddeint(model,g,tt,fargs=(180,1.0,181))

plt.plot(tt,yy)

[Zulko]

What's your error?

[Agnes159]

TypeError: 'float' object is not callable
^
Above error is shown when I input value for 'u'
where u is a step change from 0 to 0.3

[Agnes159]

Then, I try to input integer.
It shows:
TypeError: 'int' object is not callable

[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.