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wangzhou0214
3 Posts |
 Posted - 04/22/2013 : 2:04:16 PM
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OriginPro 8 SR1 v8.0773 (B773) and Service Release (Select Help-->About Origin):
Operating System:windows 7 Professional
I want to fit my datasheet by using the following function:
Y = Y0(X-X0)^t
But I did not find this function in drop-down list. How can I do the fitting or do I need to customized the function? |
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snowli
USA
1379 Posts |
Posted - 04/22/2013 : 2:24:58 PM
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Hello,
Origin supports fitting user-defined functions.
http://wiki.originlab.com/~originla/howto/index.php?title=Tutorial:User_Defined_Fitting_Function_using_OC
In 8.0, you can choose Tools: Fitting Function Organizer to define fitting functions.
You can refer to some similar built-in functions to see how to write the function body.
Don't forget to set initial values when defining the function. E.g.
E.g.
If your parameters are y0, x0, t, you can
set enter this in Parameter Setttings box
InitialValues = 1,2,3(V)
You can save the function.
Then open Nonlinear Curve Fitting dialog to fit with it.
if you didn't define initial values, you can go to Parameter tab in NLfit dialog to specify initial values as well and then fit.
Thanks, Snow |
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wangzhou0214
3 Posts |
Posted - 04/22/2013 : 5:47:36 PM
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Hello,
Thanks for your reply.
I tried to define the function by using a similar built-in function.
But it says "compile failed", does that mean at this stage I can not use this function? what should I do?
Below is a snapshot of the "compile failed" page.
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snowli
USA
1379 Posts |
Posted - 04/23/2013 : 10:04:44 AM
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It looks the parameter you defined is uppercase P.
So in function body, they should be consistent, using uppercase P.
Thanks, Snow |
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How to do exponent fitting