Matt,
Can you explain what ifeffit does when it reads a mu(E) data file
which has non-monotonically increasing energy values. Specifically
what happens to data like this:
# energy xmu
# ----------------
1 0.1
2 0.15
2 0.15
3 0.18
4 0.2
end so on.
Ifeffit throws up one of these two sets of error messages:
spline: energy data appears out of order
pre_edge: energy data appears out of order
or
spline: energy and xmu are different length?
I understand that non-monotonic data will give problems in the
intepolations and elsewhere, but what does ifeffit actually do in this
case?
FWIW, I plan to have athena check data as it is read in to verify that
the energy array is monotonic up (or down, in which case the data will
be reversed) before trying to do anything with it. But I remain
curious about what ifeffit chooses to do.
B
--
Bruce Ravel ----------------------------------- ravel(a)phys.washington.edu
U.S. Naval Research Laboratory, Code 6134 phone: (1) 202 767 5947
Washington DC 20375, USA fax: (1) 202 767 1697
NRL Synchrotron Radiation Consortium (NRL-SRC)
Beamlines X11a, X11b, X23b, X24c, U4b
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/
Howdy folks,
Today I am pleased to announce a new release of Athena and the first
release of Artemis. These are source code only releases -- I have not
yet built Windows binaries. But those of you on unix machines can
grab the latest and try them out.
Get the latest from the normal spot:
http://feff.phys.washington.edu/~ravel/software/exafs/
See some Artemis screenshots at the bottom of
http://feff.phys.washington.edu/~ravel/software/exafs/screenshots.html
Athena:
The new features are:
1. An on-line document in the Help menu
2. Plotting difference spectra and making data groups containing
difference spectra
3. Plot chi(E) (by which I mean k-weighted chi(k) but with the
x-axis converted to energy)
4. Several minor improvements to the on-screen display and to the
example files
Artemis:
Be kind. This is an initial release. ;-) Many features are
missing. Many features that are present may not work quite right.
But it does fit and plot. That's a big step!
It cannot currently do multiple data sets, but it can handle
feffNNNN.dat files from multiple feff calculations. Probably the
best way to start using Artemis is to open the example project file
for FCC copper (examples/Cu/cu.apj). Artemis can currently plot
things in k, R, or q. It can do fits or simply evaluate the path
parameters and do a sum of paths like ff2chi.
To start a project of your own, do the following:
1. Read in a chi(k) data file by selecting "Open data" from the
File menu.
2. Read in a feff calculation by selecting "Open FEFF calculation"
form the File menu and selecting the feff.inp file from the
relevant feff calculation. (You need to have already run feff,
Artemis is expecting to find the feffNNNN.dat files.)
3. Click on "Guess, Set, Def" in the column on the right and
define some fitting parameters.
4. Click on "Data' in the right column and set the fitting and FT
parameters.
5. Click on all the paths that you want to include in the fits and
define the path parameters. Like in FEFFIT, this is the time
consuming part of the process. I am open to suggestions for
helpful functionality in that part of the code.
6. Once that is all done, click on the Fit button.
7. Make plots by selecting things to plot from the right column
and clicking on the appropriate plot button. The list uses
extended selection, thus you can click and drag to select
multiple items. You can also control-click to select multiple,
disjoint items for plotting.
Play around, let me know what breaks and what needs to be added.
Remember that Athena changed A LOT in the first few months as Shelly
and Matt and others gave me feedback. It took a while, but she went
from a shaky, buggy beginning to being a useful, solid utility.
Artemis will get there, too, but I need your help to get through the
initial growing pains.
Regards,
Bruce
--
Bruce Ravel ----------------------------------- ravel(a)phys.washington.edu
U.S. Naval Research Laboratory, Code 6134 phone: (1) 202 767 5947
Washington DC 20375, USA fax: (1) 202 767 1697
NRL Synchrotron Radiation Consortium (NRL-SRC)
Beamlines X11a, X11b, X23b, X24c, U4b
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/
