The Ifeffit THANKS file

Ifeffit was written by Matt Newville (MN: newville@cars.uchicago.edu), with
considerable help and encouragement from many people. 

Many of the basic algorithms of Ifeffit are based on those of Autobk and
Feffit, which were written by MN while at the University of Washington.
Autobk and Feffit were developed under the guidance of Edward A. Stern
(EAS) and distributed as part of the UWXAFS3.0 Package by the University of
Washington.

The central idea of the core algorithm for Autobk was first presented to MN
by Yizhak Yacoby (YY) and EAS.  The idea is similar to that of J. W. Cook,
Jr and Dale E. Sayers (DES) [1], though they did not explicitly use a
Fourier transform.  The algorithm was further developed by MN and EAS for
Autobk, with many helpful suggestions from YY, Peteris Livins (PL) and John
J. Rehr (JJR).  The Autobk algorithm is described and demonstrated in [2].

The core algorithms of Feffit were developed by MN with many discussions
and suggestions from EAS, JJR, PL, YY, Bruce Ravel (BR), and Steven
I. Zabinsky (SIZ).  Feffit would not exist without the Feff program of JJR,
SIZ, Jose Mustre de Leon, and Alexei Ankudinov [3,4].  Feffit is discussed
in [5,6,7], and an early use of it is described in [8].

Many users of Autobk and Feffit over the years have greatly improved the
reliability, correctness, and functionality of Autobk and Feffit, and so
have contributed to Ifeffit.  The enthusiastic use, bug reports, and
helpful suggestions from BR, JJR, SIZ, Maoxu Qian, Anatoly Frenkel, Daniel
Haskel, Yanjun Zhang, Shelly Kelly, Chuck Bouldin, Hans Stragier, Julie
O. Cross (JOC), and Boyan Boyanov (BB) all deserve special thanks.

Ifeffit has been developed by MN while at The Consortium for Advanced
Radiation Sciences at the University of Chicago as a complete rewrite of
Autobk and Feffit.  Most of the details of Autobk and Feffit have been
altered to some extent for Ifeffit, and nearly every routine inherited from
Autobk or Feffit has been changed.  JJR, BR, and JOC have been particularly
helpful in discussing the design and features of Ifeffit.

Some of the source code in Ifeffit is based on general utilities and file
handling code originally co-authored for Autobk and Feffit by MN and BR,
and some was originally co-authored by MN and SIZ.  MN has altered or
completely rewritten all but the most trivial of these routines for
Ifeffit.  Some algorithms and code in Ifeffit are of special note:

 1  The routines in sigms.f, for the Correlated Debye Model, was originally
    written for Feff by JJR, and altered by SIZ.  MN altered it further for   
    inclusion in Feffit, and again for inclusion in Ifeffit.

 2  The code for 'error analysis', found in iff_feffit.f, iff_chieps.f, and  
    fiterr.f is inherited (though largely re-implemented) from code in 
    Feffit. The algorithms used were worked out jointly by MN, EAS, and PL,
    though  they are essentially identical to the procedures described in
    standard statistical books.  Though tested fairly thoroughly when
    implemented, a  more detailed test and analysis of Feffit's error
    analysis was done by BB and DES and published [9].  The controversial
    use of  
       N_idp = (2 Delta_k Delta_R/ pi) +2
    as described by EAS [10] and used in Feffit, has been relaxed in
    Ifeffit to be   
       N_idp = 2 Delta_k Delta_R/pi
    without the '+2'.

 3  The routines for handling and encoding mathematical expressions were
    originally written by MN but the extension of these routines by MN and
    BR for the program PHIT inspired and influenced the way in which
    Ifeffit works with arrays.

Ifeffit uses the graphics package PGPLOT of T. J. Pearson.  Due to
restrictive statements in the PGPLOT Copyright notice, PGPLOT is not
incorporated directly into Ifeffit, but should be built as a separate
library. PGPLOT is available for free for non-commercial use, and can be
found at http://astro.caltech.edu/~tjp/pgplot/.  Because of these
restrictions, it is possible to build Ifeffit without PGPLOT.

Ifeffit uses routines from the MINPACK package of J. J. More et al, the
FFTPACK package of P. N. Swarztrauber, and the PPPACK package of C. de
Boor.  The original versions of these packages are freely available from
the Netlib repository: http://www.netlib.org/.  Though the licensing status
of these codes is somewhat unclear, they are in wide use and appear to have
no restrictions on use or redistribution.  MN made some minor alterations
to routines from these packages for use in Ifeffit.  All routines from
these packages needed by Ifeffit are included in the Ifeffit distribution,
with their original copyright notices.

Ifeffit was developed almost exclusively on Linux machines using the GNU
Emacs text editor and the GNU g77 compiler.  The documentation uses the TeX
and LaTeX formatting system.  Many of the applications for Ifeffit were
written in Python and Perl, and some in Tcl. The SWIG tool was used to aid
in the creation of the interfaces to these scripting languages.  To
simplify and improve the quality of development, the CVS and RCS version
control systems have been used.  To simplify distribution and the build
procedure, Ifeffit uses GNU Make, Autoconf, and Automake.  The availability
and high quality of all of these free software packages were instrumental
in the development of Ifeffit.

Bibliography:

[ 1]  J. W. Cook, Jr and D. E. Sayers, Journal of Applied Physics, 52,
      p 5924 (1981).
[ 2]  M. Newville, P. Livins, Y. Yacoby, J. J. Rehr, and E. A. Stern, 
      Physical Review B 47, p 14126 (1993).
[ 3]  J. Mustre de Leon, J. J. Rehr, and S. I. Zabinsky, 
      Physical Review B 44, p 4146 (1991).
[ 4]  S. I. Zabinsky, J. J. Rehr, A. Ankudinov, R. C. Albers, and
      M. J. Eller,  Physical Review B 52, p 2995 (1995).
[ 5]  M. Newville, B. Ravel, D. Haskel, J. J. Rehr, E. A. Stern, and
      Y. Yacoby, Physica B 208&209, p 154 (1995).
[ 6]  E. A. Stern, M. Newville, B. Ravel, Y. Yacoby, and D. Haskel,
      Physica B 208&209, p 117 (1995).
[ 7]  M. Newville, PhD Thesis, University of Washington (1995).
[ 8]  A. Frenkel, E. A. Stern, A. Voronel, M. Qian, and M. Newville, 
      Physical Review B 49, p 11662 (1994).
[ 9]  M. Newville, B. Boyanov, D. E. Sayers, Journal of Synchrotron
      Radiation 6, p 264 (1999).
[10]  E. A. Stern, Physical Review B 48, p 9825 (1993).


