Thread Subject: exponential fitting?

Subject: exponential fitting?

From: Mario

Date: 26 Sep, 2008 17:20:04

Message: 1 of 2

Hi..
I'm dealing with this kind of data
 
x=[527.3756 546.1192 564.9728 586.4216 608.2959 630.5845 652.8730 674.8214 697.0359]

y=[193 204.1192 214.9728 219 222 224 222 219.1786 217]

and i would like to fit a*(1-exp(b*x)) (because i think it's the best curve that fits these points) and i tried to do it but i didn't get a good fit! What am i doing wrong?
I even tried to scale the data in order to place the first point in [0,0] but it didn't work as i expected (the exponential curve fit the points after it grows, so it fits the point with a line almost)

Hope you can help me!
Regards,

Mario

Subject: exponential fitting?

From: Richard

Date: 26 Sep, 2008 17:41:02

Message: 2 of 2


Using the curve fitting toolbox, an exponential model of the form
a*exp(b*x)+c*exp(d*x)

"looks" like it fits well enough.



"Mario " <nospam@yahoo.com> wrote in message <gbj5k4$5fa$1@fred.mathworks.com>...
> Hi..
> I'm dealing with this kind of data
>
> x=[527.3756 546.1192 564.9728 586.4216 608.2959 630.5845 652.8730 674.8214 697.0359]
>
> y=[193 204.1192 214.9728 219 222 224 222 219.1786 217]
>
> and i would like to fit a*(1-exp(b*x)) (because i think it's the best curve that fits these points) and i tried to do it but i didn't get a good fit! What am i doing wrong?
> I even tried to scale the data in order to place the first point in [0,0] but it didn't work as i expected (the exponential curve fit the points after it grows, so it fits the point with a line almost)
>
> Hope you can help me!
> Regards,
>
> Mario

Tags for this Thread

Add a New Tag:

Separated by commas
Ex.: root locus, bode

What are tags?

A tag is like a keyword or category label associated with each thread. Tags make it easier for you to find threads of interest.

Anyone can tag a thread. Tags are public and visible to everyone.

rssFeed for this Thread
 

MATLAB Central Terms of Use

NOTICE: Any content you submit to MATLAB Central, including personal information, is not subject to the protections which may be afforded information collected under other sections of The MathWorks, Inc. Web site. You are entirely responsible for all content that you upload, post, e-mail, transmit or otherwise make available via MATLAB Central. The MathWorks does not control the content posted by visitors to MATLAB Central and, does not guarantee the accuracy, integrity, or quality of such content. Under no circumstances will The MathWorks be liable in any way for any content not authored by The MathWorks, or any loss or damage of any kind incurred as a result of the use of any content posted, e-mailed, transmitted or otherwise made available via MATLAB Central. Read the complete Terms prior to use.

Contact us at files@mathworks.com