Re: Find a dood function for fitting data
- To: mathgroup at smc.vnet.net
- Subject: [mg42134] Re: [mg42096] Find a dood function for fitting data
- From: "Mihajlo Vanevic" <mvane at eunet.yu>
- Date: Fri, 20 Jun 2003 04:57:32 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Is this good enaugh??
In[]:=
<< Statistics`NonlinearFit`
In[]:=
data = {{0.5, 0.089}, {0.7, 0.12}, {1, 0.1652}, {2, 0.254}, {3, 0.3}, {4,
0.325}, {5, 0.34}, {7, 0.35}, {10, 0.35}, {15, 0.33}, {20, 0.32}};
In[]:=
f[x_] = NonlinearFit[data,
a1*(Exp[-b1*x] - Exp[-b2*x]), {x}, {{a1, 1.}, {b1, 2.}, {b2, 1.}},
RegressionReport -> BestFitParameters]
In[]:=
Plot[f[x1], {x1, 0.5, 20},
Epilog -> {Hue[0.], PointSize[0.02], Map[Point, data]}, PlotRange -> All]
In[]:=
data1 = {{0.5, 0.11}, {0.7, 0.15}, {1, 0.2112}, {2, 0.322}, {3, 0.37}, {4,
0.391}, {5, 0.399}, {7, 0.4}, {10, 0.38}, {15, 0.36}, {20, 0.33}};
In[]:=
f1[x_] = NonlinearFit[data1,
a1*(Exp[-b1*x] - Exp[-b2*x]), {x}, {{a1, 1.}, {b1, 2.}, {b2, 1.}},
RegressionReport -> BestFitParameters]
In[]:=
Plot[f1[x1], {x1, 0.5, 20},
Epilog -> {Hue[0.], PointSize[0.02], Map[Point, data1]}, PlotRange -> All]
Regards,
Mihajlo Vanevic
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* At 2003-06-19, 03:59:00
* guillerm, guillerm at usal.es wrote:
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>(*Dear friend, I want fit these data *)
>
>data = {{0.5, 0.089}, {0.7, 0.12}, {1, 0.1652}, {2, 0.254}, {3, 0.3}, {
> 4, 0.325}, {5, 0.34}, {7, 0.35}, {10, 0.35}, {15, 0.33}, {20, 0.32}};
>
>(*I have tested with a few function such as that the follow, but I
> have not found a good fit*)
>
>Needs["Statistics`NonlinearFit`"];
>
>fit[x1_] = NonlinearFit[data, a1 x1^b1 Exp[b2 x1], {x1}, {a1, b1, b2}]
>
>Plot[fit[x1], {x1, 0.5, 20}, Epilog -> Map[Point, data]]
>
>(*I have the same problem with this other data*)
>
>data1= {{0.5, 0.11}, {0.7, 0.15}, {1, 0.2112}, {2, 0.322}, {3, 0.37}, {4,
>0.391}, {5, 0.399}, {7, 0.4}, {10, 0.38}, {15, 0.36}, {20, 0.33}};
>
>(*I will appreciate if you find a good fit, with no many parameters, for both
>data. Thanks
>Guillermo
>Sanchez*)
>
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