[Ifeffit] Bugs in new versions of Athena and Artemis

Bruce Ravel ravel at phys.washington.edu
Thu Mar 11 10:22:13 CST 2004


On Thursday 11 March 2004 08:43 am, Schmithals wrote:
> - Making 'Sum of paths (no fit)' produces no output (when no data file
> is loaded).
> In 'Co Cubic 2.apj' I set up an Atoms page and ran the FEFF calculation.
> When choosing 'Sum of paths (no fit)' | all paths from the menu it will
> indicate a correct calculation but when trying to plot the fit it will
> fail.

This project file is triggering several repititions of the same bug.
The bug (my fault!) is triggered by not having data in the project.  I
believe that you can avoid this issue simply by importing a data
file.  It doesn't even have to be a relevant data file if all you want
to do is look at the sum of paths.

I acknowledge that one can reasonably want to do a sum of paths
without importing data.  It is my intent that such a thing should be
possible and I will work to make it so in the next release.


> - Data file can not be read in:
> When I read in a datafile (Data | Change data file) Athena will correcly 
> show up a dialog and display the data in k-space in the graph window. 
> Any subsequent click on k, R or q-buttons will give the error message: 
> "You have not yet loaded data ...". I am not be able to save the 
> datafile, instead an error message will occur "You cannot write the 
> artemis description file". I tried it with my own data (exp005_absW.chi) 
> and with an example file (cu010k.chi).

Again, I cannot reproduce this problem.  This simply does not happen
for me.

Are there any interesting messages in the command window?

>  If I first set up a FEFF calculation and afterwards import a data file 
> I am able to plot the data file in k-space but in R-space it will only 
> show a horizontal line. When fitting always a warning message will 
> appear: "There are errors in your math expressions ...". "Co Cubic 
> 3.apj" is an example of such a file. As you can see, the folder chi_data 
> in the zip-file contains no data.

I can reproduce this starting with your project file, but I cannot do
so starting from scratch, saving the project, reopening the project,
then reading some data in.  I did notice that, when staring with your
project file, the kmax for the Fourier transform to 0, then the data
will plot in k but will be a horizontal line at 0 in R.  That seems
like correct behavior to me.  Did you check your k-range values?
Setting kmax to something sensible makes for a sensible FT.

As for the fitting message -- I should check to see that kmax > kmin
and Rmax > Rmin.  I currently do not make that check.

B




The basic flowchart for an Artemis 0.7 project is this: (1) import
data, (2) import or create atoms data, (3) run atoms, (4) check the
feff.inp data and run feff, (5) set up your fitting model, (6) hit the
big green button.

Certainly you should be able to deviate from that script, but if you
run into some problem with the code, it may be prudent to follow it.

B


-- 
 Bruce Ravel  ----------------------------------- ravel at phys.washington.edu
 Code 6134, Building 3, Room 405
 Naval Research Laboratory                          phone: (1) 202 767 2268
 Washington DC 20375, USA                             fax: (1) 202 767 4642

 NRL Synchrotron Radiation Consortium (NRL-SRC)
 Beamlines X11a, X11b, X23b
 National Synchrotron Light Source
 Brookhaven National Laboratory, Upton, NY 11973

 My homepage:    http://feff.phys.washington.edu/~ravel 
 EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/



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