Re: NonlinearFit
- To: mathgroup at smc.vnet.net
- Subject: [mg42161] Re: NonlinearFit
- From: gohtk at rocketmail.com (goh tat kean)
- Date: Sat, 21 Jun 2003 02:49:37 -0400 (EDT)
- References: <bcrrkf$hp6$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Dear Rees,
My suggested solution goes below:
data = {{0.1, 0.113387476}, {0.2, 0.194633152}, {0.3, 0.252848224}, {0.4,
0.294561145}, {0.5, 0.324449759}, {0.6, 0.345865887}, {0.7,
0.361211213}, {0.8, 0.37220662}, {0.9, 0.380085173}, {1.0, 0.385730403}};
To see how your data look like,
gr1 = ListPlot[data]
Load the NonlinearFit package,
<< Statistics`NonlinearFit`
Define your fit function as,
ft1 = NonlinearFit[data, c*(1 - Exp[-3*x/a]), x, {c, a}, ShowProgress -> True]
Note the correct way of exponential term is Exp[-3*x/a] not Exp(-3*x1/a).
c = 0.4, a = 0.9
Plot the fitted curve and show it together with your data.
gr2 = Plot[ft1, {x, 0, 1}]
Show[gr1, gr2]
Good luck.
Regards,
tat kean
civnrn at hotmail.com (Rees) wrote in message news:<bcrrkf$hp6$1 at smc.vnet.net>...
> Hi,
>
> Please could someone assist me in curve fitting.
>
> I have the following x,y data
>
> data = {{0.1,0.113387476}, {0.2, 0.194633152}, {0.3,
> 0.252848224}, {0.4, 0.294561145}, {0.5,
> 0.324449759}, {0.6, 0.345865887}, {0.7,
> 0.361211213}, {0.8, 0.37220662}, {0.9,
> 0.380085173}, {1.0, 0.385730403}};
>
> Now I wish to fit an exponential curve of the form below to it:
>
> c*[1-Exp(-3x/a]
>
> where c and a are parameters to be determined.
>
> I tried the following but it doesn't work:
>
> NonlinearFit[data, c*(1 - Exp(-3*x1/a)), {x1}, {c, a}]
>
>
> Please advise.
>
> Thanks is advance
>
> Rees