R help - Oct 2005 - Fitting of Non-Linear Diff Equations and Parameter Estimation

Hello Everybody,
I am running R 2.2.0 with Windows XP
i am trying to fit nonlinear differential equation to data sets which looks
like this:
Week N C
0 1 1
1 5 6
2 6.2 12.2
3 59 71.2
4 39 110.2
5 38 148.2
6 44 192.2
7 20.4 212.6
8 19.4 232
9 34.2 266.2
10 35.4 301.6
 and i need to fit these data to the following diff equation:
dNdt=a*N-b*N*C, dCdt=N^2,
Where a=birth rate, b=death rate and N= Current count, C= Cumulative Count.
i need to fit the differential equation, solve and obtain parameters a,b.
can someone help with this,
Thanks
Raj

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Raja Jayaraman <rajnmsu79 <at> gmail.com> writes:
> 
> Hello Everybody,
> I am running R 2.2.0 with Windows XP
> i am trying to fit nonlinear differential equation to data sets which looks
> like this:
[SNIP]
>  and i need to fit these data to the following diff equation:
> dNdt=a*N-b*N*C, dCdt=N^2,
> Where a=birth rate, b=death rate and N= Current count, C= Cumulative Count.
> i need to fit the differential equation, solve and obtain parameters a,b.
> can someone help with this,
> Thanks
> Raj
Try looking at the package odesolve for solving the ode system.

Woody Setzer
National Center for Computational Toxicology
US EPA