RE: NonlinearFit
- To: mathgroup at smc.vnet.net
- Subject: [mg42130] RE: [mg42109] NonlinearFit
- From: "David Park" <djmp at earthlink.net>
- Date: Fri, 20 Jun 2003 04:57:29 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Rees,
Functions use [] (not ()) to enclose the arguments. And you have to load the
package first.
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., 0.385730403}};
Needs["Statistics`NonlinearFit`"];
f[x1_] = NonlinearFit[data, c*(1 - Exp[-3*x1/a]), {x1}, {c, a}]
0.40000000043347517*(1 - E^(-3.33333333010406*x1))
Plot[f[x1], {x1, 0.0, 1}, Epilog ->
{AbsolutePointSize[4], Point /@ data},
PlotRange -> All];
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: Rees [mailto:civnrn at hotmail.com]
To: mathgroup 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