The Origin Forum
File Exchange
Try Origin for Free
The Origin Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ | Send File to Tech support
 All Forums
 Origin Forum
 Origin Forum
 Curve fitting data with x error bounds

Note: You must be registered in order to post a reply.
To register, click here. Registration is FREE!

Screensize:
UserName:
Password:
Anti-Spam Code:
Format Mode:
Format: BoldItalicizedUnderlineStrikethrough Align LeftCenteredAlign Right Horizontal Rule Insert HyperlinkUpload FileInsert Image Insert CodeInsert QuoteInsert List
   
Message:

* HTML is OFF
* Forum Code is ON
Smilies
Smile [:)] Big Smile [:D] Cool [8D] Blush [:I]
Tongue [:P] Evil [):] Wink [;)] Clown [:o)]
Black Eye [B)] Eight Ball [8] Frown [:(] Shy [8)]
Shocked [:0] Angry [:(!] Dead [xx(] Sleepy [|)]
Kisses [:X] Approve [^] Disapprove [V] Question [?]

 
Check here to subscribe to this topic.
   

T O P I C    R E V I E W
ramcd Posted - 12/14/2014 : 7:19:39 PM
I have location vs time data and want to obtain speed by curve fitting. The measured time has uncertainty while the locations do not. The data with time on x-axis and locations on y-axis seem to follow an exponential relation. So I am trying to curve fit an exponential curve keeping the time data on x-axis and locations on y-axis. How do I include the error in time (which is on x-axis) in the fitting routine?


rcd
5   L A T E S T    R E P L I E S    (Newest First)
ramcd Posted - 12/15/2014 : 01:12:45 AM
quote:
Originally posted by Shirley_GZ

Please tell me which function you are using to fit the data. Or send us the project via tech@originlab.com and quote this post.

Originlab Technical Service Team


sent the project file

rcd
Shirley_GZ Posted - 12/15/2014 : 12:42:36 AM
Please tell me which function you are using to fit the data. Or send us the project via tech@originlab.com and quote this post.

Originlab Technical Service Team
ramcd Posted - 12/14/2014 : 11:34:54 PM
Just an update, the result doesn't change even if I vary the errors in column C. It seems that the error bounds are somehow not getting included in the fitting routine...

rcd
ramcd Posted - 12/14/2014 : 11:17:27 PM
Hello,

Thank you for helping out. I tried using the ODR algorithm to fit an exponential curve- firstly by not including the error bounds, and secondly by including the error bounds. However, I am getting exactly same curve fits, statistics of fit, etc. While neglecting the errors, I select 'no weights' option in the Data Selection menu of the NLfit program. On the other hand, to include the errors I first set the error column as 'x-error', then select the 'Use Each Range Setting' option in NLfit. I run the curve fitting routine, but get exactly same fits and statistics in both the cases. Am I missing out on something?

To help you, I attache a snapshot of my data in OriginPro

rcd
Shirley_GZ Posted - 12/14/2014 : 10:24:20 PM
Hi,

Since Origin 9.1, OriginPro supports ODR (Orthogonal Distance Regression), you can use it to do fitting with X error.



Any problem, please let me know.

Thanks,
Shirley

Originlab Technical Service Team

The Origin Forum © 2020 Originlab Corporation Go To Top Of Page
Snitz Forums 2000