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
 Can not fit Hill Equation when n =-1		  New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic

mklab2

USA
1 Posts
Posted - 05/04/2013 :  12:54:23 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
I am trying to fit Hill equation

y=Vmax X^n/((K^n+X^n))

when n is >0, it is fitting fine,

but when n = -1 , or some number < 0, it can not fit. It shows:

"Fit did not converge - mutual dependency exists between parameters.
You may have overparameterized the fitting function. Fixing one of them may eliminate this problem."

and give me a horizontal line
Please help me , what is the problem with the fitting ? ( I did not change anything with the function)

Sam Fang

293 Posts
Posted - 05/06/2013 :  11:07:06 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Origin's built-in Hill function has a constraint by default:
n > 0


You can remove the constraint if n<0 in NLFit dialog's Bounds tab as shown below.



Sam
OriginLab Technical Services
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