Hi, The easiest constraint would be a mathematical expression such as "a + b = 1". Do you have an experimental value for so2 as found for something chemically similar such as a standard at that edge? Then replace so2 expression for each path as "value found * a" and "value found * b". This should give a relative percentage for each path contribution.
Hope that is clear, Chris ******************************************** Dr. Christopher Patridge Assistant Professor of Chemistry Math and Natural Science Dept BFAC 009 D'Youville College 320 Porter Ave., Buffalo, NY 14150 716-829-8096 Sent from my iPhone > On Feb 28, 2014, at 7:52 AM, Cristina Alonso Escobar <cria...@itq.upv.es> > wrote: > > Dear All, > > I am trying to fit the first FT shell in Artemis with a mixture of two > different compounds (octahedral and tetrahedral models). I would like to > quantify the ratio between this two compounds in my sample so I decided to > multiply So2 by a parameter called "a" in one model and by "(1-a)" in the > other. > > I would like to know: > > 1.- How can I restrain "a" ? I tried to manually add a restraint, but I do > not know how to make an interval restraint...( 0<a<1) > > 2.- If you select "restrain" and after in the math expression "build restrain > from ..." > What is the meaning of scale by? > Why the program duplicate the restrain (i.e restrain- a and restrain- res_a - > 1* penalty (a, 0, 1)? > I think I am not doing well because the value of my parameter "a" is > suspiciously always 0. > > > > Thank you in advance, > > > > *** *** *** *** *** *** *** *** *** > > Cristina Alonso-Escobar. PhD student > > Instituto de Tecnología Química (UPV-CSIC) > Avda. de los Naranjos s/n > 46022 Valencia (Spain) > > http://itq.upv-csic.es > > Tfno: +34 96 387 7800 > Fax: +34 96 387 9444 > > ----- Terminar mensaje reenviado ----- > > > *** *** *** *** *** *** *** *** *** > > Cristina Alonso-Escobar. PhD student > > Instituto de Tecnología Química (UPV-CSIC) > Avda. de los Naranjos s/n > 46022 Valencia (Spain) > > http://itq.upv-csic.es > > Tfno: +34 96 387 7800 > Fax: +34 96 387 9444 > > _______________________________________________ > Ifeffit mailing list > Ifeffit@millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit