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
Username:
 Password:
Save Password
Forgot your Password? | Admin Options

 All Forums
 Origin Forum
 Origin Forum
 Non linear curve fit does not match with 2D plot		  New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic

bananas555

Canada
2 Posts
Posted - 06/05/2016 :  10:09:13 PM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
I have a set of data that I've peak fitted with a custom equation using the non linear curve fitting tool.

When I enter this custom equation in the 2D function plot tool (with the exact same parameters), the output peak fit is not the exact same. I'm unsure as to why this is happening.

Any ideas?

Echo_Chu

China
Posts
Posted - 06/06/2016 :  02:20:38 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi,

We should pay attention to the coefficient values used in the 2D function plot tool. The number of significant digits used when copying the coefficient values may greatly alter the subsequent computation.

Could you try following steps in copying the parameter values from the fitting result?

1. Highlight the parameter values in the result sheet
2. Press Ctrl + Alt + C (It is to copy the values in full precision)

Then you can Ctrl + V to paste the values in full precission for the use in 2D funciton plot tool.

Echo
OriginLab Technical Support
Go to Top of Page

bananas555

Canada
2 Posts
Posted - 06/06/2016 :  11:33:56 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi,

I've done exactly that, but still does not match up with the fitted result.

The fit from the 2D function plot tool appears to be smaller than the actual fit from the non linear curve fitting tool.

When I manually increase the area of the function in the 2D plot, it better matches the actual fitted data. I'm thinking that there is something that is subtracting or rescaling the area of the function in the 2D plot perhaps?
Edited by - bananas555 on 06/06/2016 11:53:18 AM
Go to Top of Page

Echo_Chu

China
Posts
Posted - 06/06/2016 :  10:11:18 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Would you mind sending us your project file so that we can further identify the problem?

You could follow the instructions below to send your file.
http://www.originlab.com/index.aspx?go=Support&pid=752
Go to Top of Page
  Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
The Origin Forum © 2020 Originlab Corporation Go To Top Of Page
Snitz Forums 2000