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
 Implementing a Broken Power Law to fit with		  New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic

Verdict

2 Posts
Posted - 11/26/2014 :  10:36:19 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Good day, I'm trying to use the function builder in origin (OriginLab) to create a new function to fit with, the broken power law (http://en.wikipedia.org/wiki/Power_law#Broken_power_law)

So, I think I got the actual function part down. For this I used

if(x<xc)
y =x^a1;
if(x>xc)
y = x^(a1-a2)*x^a2;
if(x==xc)
y = 0;

Where xc, a1 and a2 are the parameters. However, I then get to the point where you have to choose a bunch of stuff (parameter ranges, script you run to guess initial values, etc) and I have no clue what to put in there. Does anyone have some experience with this?

jasonzhao

China
262 Posts
Posted - 11/27/2014 :  01:20:27 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hello,

Initialization code, bounds, script before fitting is not necessary input items for building a fitting function:

you can refer to this tutorial:
http://www.originlab.com/doc/Tutorials/UserDef-FitFunc

you can also use this general formula (Labtalk script Function type) for simplify:


y=k1*x^a1*(x<th)+k2*th^(a1-a2)*x^a2*(x>th)


Best regards,
Jason Zhao
OriginLab Tech Service
Edited by - jasonzhao on 11/27/2014 01:23:59 AM
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