On 10/13/2016 05:17 PM, Dimitar Popmintchev wrote:
I would like to ask, after a fit (in Artemis) which column in the output
file gives the uncertainty for peaks position dR (R+/-dR i.e. 3+/-0.02
Angstroms) ?
Error bars are not propagated in Artemis currently. That's something you, the user, has to do using the math expression that relates your variable(s) to the delta R in question.
The simplest common case is one where you have
guess delr = 0
then later, for some path,
reff = 3.0
deltaR = delr
In that case, delr is varied and the path length is 3.0 + delr.
Propagating the uncertainty in this case is trivial:
delta( 3.0 + delr) = delta(3.0) + delta(delr)
3.0 is a constant, so the error bar in the path length is the same as the error bar in the variable.
HTH,
B
--
Bruce Ravel ------------------------------------ bravel@bnl.gov
National Institute of Standards and Technology
Synchrotron Science Group at NSLS-II
Building 743, Room 114
Upton NY, 11973
Homepage: http://bruceravel.github.io/home/
Software: https://github.com/bruceravel
Demeter: http://bruceravel.github.io/demeter/
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