Re: optimizing
- To: mathgroup at smc.vnet.net
- Subject: [mg74902] Re: optimizing
- From: dh <dh at metrohm.ch>
- Date: Tue, 10 Apr 2007 06:02:01 -0400 (EDT)
- References: <evabpk$df6$1@smc.vnet.net>
Hi,
your model function has the form: Exp[-k t], no need to solve an DE. Now
you have the model function and your data and you can e.g. use "FindFit"
to get the obtimal k.
Daniel
kaiwan wrote:
> Hi! I have to find the best parameter "k" with witch function sd[k]->minimum. I do that with FindMinimum. "sd" if a function that calculates the standard deviation from my experimental and model data. The model data is obtained from the mathematical model, first order differential equation...which I solve using NDsolve. The problem is that I cant make NDSolve work under FindMinimum.
>
> Something like this:
> First, I define function that hace to solve the equation c'[t] == -k c[t], where "k" is a variable. This gives me model data later on. I define it as a function cause I dont know the value of "k" yet.
>
> Then I define another function which calculates the standard deviation:
> sd[k_]:= function(model data, experimental data)
>
> Still I have no concrete results.
>
> Then I use FindMiniumm for finding the "k" that gives the smallest Standard Deviation
> FindMinimum[sd[k], {k, 0.04}]
>
> And her is the problem, I cant make this combination to work .... help please? Many thanks!
>