Re: NonlinearFit for specific data
- To: mathgroup at smc.vnet.net
- Subject: [mg117852] Re: NonlinearFit for specific data
- From: Sseziwa Mukasa <mukasa at gmail.com>
- Date: Fri, 1 Apr 2011 02:37:00 -0500 (EST)
On Mar 31, 2011, at 5:01 AM, Alexandre Souza wrote:
> Dear Group,
> I have the following data :
> data2 = { {0, 773.59},{30, 2351.12},{60, 4205.8}, {90, 4222.69},{120,
> 4222.69},{150, 704.328},
> {180, 1388.28},{210, 1388.28},{240, 1821.23},{270, 1821.23},{300,
> 754.109},{330, 773.59},{360, 773.59}};
> I want the following curve fit :
> NonlinearFit[data2, Exp[ a + b x + c x^2], x, {a, b, c}]
> Unfortunatelly I get some "FindFit::sszero
> FindMinimum::sszero" message, and the given result is ackward.
> I also tried FindFit and NonlinearRegress without success.
> Any comment would be very welcome.
> Alex
>
(Debug) In[142]:= data2 = {{0, 773.59}, {30, 2351.12}, {60, 4205.8}, {90, 4222.69}, {120,
4222.69}, {150, 704.328}, {180, 1388.28}, {210, 1388.28}, {240,
1821.23}, {270, 1821.23}, {300, 754.109}, {330, 773.59}, {360, 773.59}};
FindFit[data2, Exp[a + b x + c x^2], {a, b, c}, x]
(Debug) During evaluation of In[142]:= FindFit::cvmit : "Failed to converge to the requested accuracy or precision \
within 100 iterations.
(Debug) Out[143]= {a -> -87.9807, b -> 0.938303, c -> 1.00009}