[R-sig-dyn-mod] Modeling dampened oscillator with random resets

[Felix Schönbrodt]

Dear list,

using deSolve (or another package): is it possible to model a dampened oscillator that is reset to new states at specific points?

Background: I want to model a system that tries to approach equilibrium, but is disturbed at single events. It would roughly look like following screenshot:
https://dl.dropbox.com/u/4472780/WP/oscReset.PNG

In this screen shot, events at t=70 and t=120 disturb the oscillator. In this screen shot I simply pasted together 3 independent plots; but if the disturbance is directly modeled it should somehow be reflected in the dx etc. (e.g., at the second event I would expect that the curve first continues going up before it is regulated down again).

Here's my function for the dampened oscillator:

library("deSolve")

	osci <- function (t, states, parms) {
	 with(as.list(c(states,  parms)), {
	   dx <- y
	   dy <- eta * x + zeta * y
	   list(c(dx, dy))
	 })
	}

	states <- c(x=1, y=0)
	out <- data.frame(ode(states, osci, times = 1:100, parms = c(eta = -0.05, zeta = -0.02)))
	plot(out)


Best,
Felix