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.


 Bruce Ravel  ------------------------------------ bra...@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
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