| T O P I C R E V I E W |
| sombrancelha |
Posted - 08/30/2008 : 3:48:13 PM
Hello,
I'm using Origin 8 and I'd like some help to fit a curve into my points.
I want to fit something in the form:
y = A*ln(B*x+1)
How can I do that?
Also, for the calculation of the precision of A and B, it's important that it considers both errors in X and in Y.
Thanks in advance. |
| 3 L A T E S T R E P L I E S (Newest First) |
| Fay_Guo |
Posted - 09/02/2008 : 06:04:11 AM
Hi Sombrancelha,
I am sorry to tell you that current version of Origin does not support fitting with X errors for the build-in functions.
While Origin supports two methods of using Y error as value for weights.
For more information about it, please see here:
http://www.originlab.com/www/helponline/Origin8/en/origin.htm#Regression_and_Curve_Fitting/Simple_Linear_Regression_Dialog.htm#Fit_Options
Thanks
Fay
Originlab Technical Services |
| sombrancelha |
Posted - 09/01/2008 : 7:08:47 PM
Does Origin supports fitting with X errors for the built-in functions, such as y = ax + b? |
| Deanna |
Posted - 08/31/2008 : 10:20:25 PM
Hi Sombrancelha,
You can create a user-defined function in the form you need and then use it in the Non-Linear Curve Fitting dialog to perform the fitting. Please see here for details on how to define a user-defined function:
http://www.originlab.com/www/helponline/Origin8/en/origin.htm#Regression_and_Curve_Fitting/User-Defined_Fitting_Functions.htm
I am sorry that current version of Origin does not support fitting with X errors. We apologize for the inconvenience. We are considering adding this feature in our next version.
Deanna
OriginLab Technical Services |
