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 "linear" constraints in nonlinear fit		  New Topic  Reply to Topic
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karvek

13 Posts
Posted - 04/06/2016 :  04:04:47 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Hi all,

I am fitting some datasets with a user-defined function.
I have something of the kind:
f = Ax + By + Cz.
A, B and C must be in the interval [-1,1] that I can set in the parameters bounds.

However I would like to use as a general linear constraint something like abs(A) + abs(B) + abs(C) = 1.

If I don't use the absolute value it works quite well but of course the sum is messed up by possible negative negative values of the parameters.

Anyone has an idea on how to implement this?
The function is written in Origin C.

Origin 9.1 (64-bit) Sr2
Operating System: Windows 7

SeanMao

China
288 Posts
Posted - 04/06/2016 :  04:21:44 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi,

Can you send me a copy of your data and the fitting function FDF file to tech@originlab.com so that I can have a try on my side to see the problem?

Regards!

Sean

OriginLab Tech.
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