General Questions on Ifeffit and XAFS

Contents

  1. General Questions on Ifeffit and XAFS
    1. What is Ifeffit?
    2. How can I add to or edit this FAQ?
    3. What programs come with the Ifeffit Distribution?
    4. How is IFEFFIT different from FEFFIT? From AUTOBK?
    5. How can I contribute to the Ifeffit project?
    6. How can I join the IFEFFIT Mailing list?
    7. The IFEFFIT Mailing list says my message "Requires Approval". Why?
    8. How can I search the IFEFFIT Mailing list?
    9. How do I add a new FAQ entry?

What is Ifeffit?

IFEFFIT is a collection of algorithms, procedures, and programs for XAFS Analysis. It includes high-quality algorithms specific to XAFS Analysis: For background removal, it uses the AUTOBK algorithm, and for fitting EXAFS chi(k) and FEFFIT with graphical display of XAFS data and general data manipulation.

This means that there isn't one single thing called "IFEFFIT". Rather, "IFEFFIT" has a few different meanings. Here, we'll use:

IFEFFIT: At it's most basic level, IFEFFIT is a programming library that includes a full set of procedures and algorithms for dealing with XAFS data. The algorithms of the older programs Autobk and Feffit are all included in IFEFFIT library. This library can also be used within other programs or scripts, so that a variety of small programs and general-purpose user interfaces (both graphical and non-graphical) can be written around it. Several such tools are now included in the IFEFFIT distribution.

ifeffit: Written in all lower-case, ifeffit refers to the command-line program that allows interactive processing, plotting, and analysis of XAFS data. Compared to the GUIs available using Ifeffit, this program is a very low-level way to use the Ifeffit library. It is command driven, but very flexible and fast. At this point it's probably better to start using Ifeffit with a GUI, but if you're really analyzing lots of data, you may find it worth the effort to understand how the ifeffit program works.

Ifeffit+Friends: This refers to the full suite of libraries, programs, GUIS, and documentation related to Ifeffit. The distributions of Ifeffit for Windows, Mac OS X, and unix all install more than just the base library.

Contents

How can I add to or edit this FAQ?

You can add to or edit this FAQ by logging into this Wiki and adding or editing the content of the Frequently Asked Questions pages. See the last question question on this (or any other) Ifeffit FAQ page or HowToUseThisWiki for more details.

Contents

What programs come with the Ifeffit Distribution?

Ifeffit+Friends distribution comes with several applications based on the IFEFFIT library. The exact list of programs depends somewhat on which computer system is used. For all platforms (and included in the Ifeffit source kit), these programs are included:

On Windows, these Graphical User Interface (GUI) programs are also included:

For Mac OS X (10.2 to 10.4), these GUIs are included:

On Unix systems, athena, artemis, and hephaestus can be installed separately using the horae_update script in the Ifeffit source kit.

For Unix (and Mac OS X 10.3), the command-line program diffkk for doing differential Kramers-Kronig transform of DAFS data is also included.

The source code and the latest version of SixPack is available from Sam Webb's web site: http://www-ssrl.slac.stanford.edu/~swebb/sixpack.htm

The source code for Bruce's GUI programs Athena, Artemis, and Hephaestus are easy to build and install on any computer with Ifeffit, PGPLOT, perl, and perl/Tk already installed. The source code package are at Bruce's Software Page or from the Ifeffit sourceforge.net page

Contents

How is IFEFFIT different from FEFFIT? From AUTOBK?

IFEFFIT is derived from AUTOBK and FEFFIT, and so has a lot in common with both of them. IFEFFIT completely replaces AUTOBK and almost all of the capabilities of FEFFIT as well. The syntax for IFEFFIT is different from that of AUTOBK and FEFFIT. In many ways this is an improvement as it allows a lot more flexibility in data processing. It does, however, mean that input files for AUTOBK and FEFFIT are not directly supported in IFEFFIT.

In addition, IFEFFIT provides graphics capabilities, an interactive session, and more flexible data analysis than AUTOBK or FEFFIT provides.

FEFFIT is a sophisticated XAFS fitting program, especially good at complex data analysis - multiple data set fits, generalized fitting variables, and robust error analysis. These capabilities are completely re-implemented in IFEFFIT, and IFEFFIT even has some XAFS-fitting capabilities that FEFFIT does not.

Contents

How can I contribute to the Ifeffit project?

There are lots of things that programmers and non-programmers can do!

Here is a list of Matt's suggestions: http://cars9.uchicago.edu/ifeffit/HowToHelp and here is a list of Bruce's suggestions: http://millenia.cars.aps.anl.gov/pipermail/ifeffit/2003-October/000507.html

Contents

How can I join the IFEFFIT Mailing list?

Just sign up at http://cars9.uchicago.edu/mailman/listinfo/ifeffit/. It's that easy!

The conversation ranges from questions about XAS theory and experimentation to use of the Ifeffit+Friends software. We also welcome posts about upcoming conferences and workshops related to XAS and post-doctoral opportunities in groups that do XAS.

Contents

The IFEFFIT Mailing list says my message "Requires Approval". Why?

The Ifeffit Mailing list at

only accepts (and passes on) mail from its subscribers. It's pretty dumb, and all it's looking for is that the "From:" field in the message exactly matches one of the subscribing email addresses.

As an example, if bob@uni.edu is subscribed, mail "From:" bob@dept.uni.edu or bob002@someyahoo.com would be held for approval, even if they all go to the same person.

If you get a message that your posting is being held for approval, don't panic - we will approve all legitimate mail, and are only using this process to reject obvious spam. The approval process is easy, and usually happens as soon as one of the list administrators reads their email.

It is easy to add addresses to the list of addresses to always accept mail from (so we could add bob@dept.uni.edu above, for example). In fact, we normally do add such 'secondary' addresses when legitimate messages are posted.

Contents

How can I search the IFEFFIT Mailing list?

Old messages in the mailing list are archived at http://millenia.cars.aps.anl.gov/pipermail/ifeffit/

The archive is sorted by date and split into single months. Therefore, finding old contributions by keyword would hardly be possible - if there wasn't google.

Try going to http://www.google.com/ and restrict your search to pages that match the site of the mailing list. This is done using the "site:" directive. Entering

will return a hit for every entry in the archive that discusses spline clamps.

Contents

How do I add a new FAQ entry?

Edit this section, use copy and paste! Use a format like this, using the same level of header (i.e. the same number of = signs) and keeping the link back to the contents at the top of the page: 

== How do I add a new FAQ entry? ==
     Edit this section, use copy and paste! 
[#contents Contents]
----

Contents

FAQ/General_Questions (last edited 2009-10-09 19:46:34 by localhost)