[GSAS-II] Can Parameters be restricted?

[Toby, Brian H.]

No.

To be honest I am not sure why one would want to do this. When a parameter refines "out of range” it tells you something about your data or model. With a restraint, you would never know that for example, a Uiso value is refining negative by > 2 sigma or a occupancy is >>1. It makes sense to me to define a model so that the sum of occupancies is fixed — a well defined assumption. Defining a range for a parameter scares me as I could never know that my model is highly flawed is some way.

Brian

On Sep 12, 2016, at 10:27 AM, Ivo Alxneit <ivo.alxneit at psi.ch<mailto:ivo.alxneit at psi.ch>> wrote:

Dear all

is there a way to restrict fitted parameters to a certain range? For
example restrict site occupancies to positive numbers or to a range such
as 0.9-1.0?

thanks for any help
--
Dr. Ivo Alxneit
Catalysis for Energy Group
Bioenergy and Catalysis Laboratory        phone: +41 56 310 4092
Paul Scherrer Institute                     fax: +41 56 310 2688
CH-5232 Villigen                      gnupg key: 0x515E30C7
Switzerland
https://www.psi.ch/ceg/catalysis-for-energy-group/

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