I have not thought about if your constraint is a good idea, but I want to confirm that this type of constraint is not allowed within the current GUI.
The underlying constraint mechanism within GSAS-II would allow it to be included if input, but I am not sure how to write an interface that allows input and editing of completely general constraints. Brian On Oct 18, 2016, at 8:10 AM, Ivo Alxneit <ivo.alxn...@psi.ch<mailto:ivo.alxn...@psi.ch>> wrote: Dear all I have a series of X-ray powder diffractograms that show the segregation of platinum from Pt4+ doped ceria. I would like to analyze the segregation kinetics from these data. I fit the Histogram Scale Factor and define a constrain that all phase fractions add up to 1.0. For consistency I would like to set up a constrain of the form 0:0:Scale * 0::Afrac:3 + 1:0:Scale fraction_doped_ceria * Pt4+ occupancy plus fraction_segregated_platinum i.e. a constrain that makes the amount of platinum in the system constant (under the assumption that all platinum is 'visible' i.e. no X-ray amorphous Pt clusters are present). At present (Rev 2493) this does not seem to be possible and I try to manually set the correct Pt4+ occupancy. This is rather tedious iteration process. Could this be implemented in GSASII or is my analysis faulted? Thanks for any suggestions -- 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/ _______________________________________________ GSAS-II mailing list GSAS-II@mailman.aps.anl.gov https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii ******************************************************************** Brian H. Toby, Ph.D. office: 630-252-5488 Advanced Photon Source Chief Computational Scientist Senior Physicist/Computational X-ray Science Group Leader 9700 S. Cass Ave, Bldg. 401/B4192 cell: 630-327-8426 Argonne National Laboratory Argonne, IL 60439-4856 e-mail: brian dot toby at anl dot gov ******************************************************************** "We will restore science to its rightful place, and wield technology's wonders... We will harness the sun and the winds and the soil to fuel our cars and run our factories... All this we can do. All this we will do."
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