| Author |
Comment/Response |
xage
|
 02/08/12 02:29am
Hey,
i want to simulate a demographic transition for a model given by 6 differential equations.
The important parameter (d) needs to be changed while i solve the system, using NDSolve.
olc = NDSolve[{P'[t] == dP[P[t], k[t], S[t], n[t], c[t], e[t]],
P[0] == P0 + ic[[1]],
k'[t] == dk[P[t], k[t], S[t], n[t], c[t], e[t]],
k[0] == k0 + ic[[2]],
S'[t] == dS[P[t], k[t], S[t], n[t], c[t], e[t]],
S[0] == S0 + ic[[3]],
n'[t] == dn[P[t], k[t], S[t], n[t], c[t], e[t]],
n[0] == n0 + ic[[4]],
c'[t] == dc[P[t], k[t], S[t], n[t], c[t], e[t]],
c[0] == c0 + ic[[5]],
e'[t] == de[P[t], k[t], S[t], n[t], c[t], e[t]],
e[0] == e0 + ic[[6]]}, {P, k, S, n, c, e}, {t, tmin, tmax}]
I would like to change d in the intervall 2/5(tmax-tmin)<t<3/5(tmax-tmin) with steps d[t]*0.99 (representing lower mortality)
I tried two ways
1.) to add d'[t]=d[t]*0.99 as another differential equation, but i don't know how to trigger it to start and end at certain t-values inside NDSolve (can i use if somehow?)
2.) use "EventLocator". Couldn't complete it.
How may I solve this issue?
Thanks
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