Go to the first, previous, next, last section, table of contents.

@macro ease{} {@sf EASE} @ifnottex EASE

@direntry * EASE: (ease). EXAFS Analysis System for Emacs

The author of {@sf EASE}, Bruce Ravel, can be reached at:

@email{<ravel@phys.washington.edu>}

The latest version of {@sf EASE} can always be found at
@url{http://feff.phys.washington.edu/~ravel/ease/}

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice must be stated in a translation approved by the author.

Introduction to EASE

This document describes the installation and use of @ease{}. @ease{} is the EXAFS Analysis System for Emacs. It is a user interface for FEFF, ATOMS, AUTOBK, FEFFIT and a few other programs.

This document is written with the assumption that the reader is familiar with EXAFS analysis, the use of FEFF and FEFFIT, and the use of Emacs. It is not expected that the reader is a guru in any of these topics, but a certain knowlege of each is necessary as their basic concepts will not be explained here.

There are two companion documents to this one. One of these is a tutorial (see section `Introduction' in The Ease Tutorial) and demonstrates the use of @ease{} by walking you through an analysis of copper metal using @ease{} along with FEFF and FEFFIT. The other is a quick reference card, `quickref.ps', which describes the key sequences and user configurable variables in @ease{}. These three documents together provide a complete reference to @ease{}.

The general purpose of a user interface to these (or any) programs is to to add value to the programs by making their use easier and more efficient. To this end, I have broken down the interface to FEFF and FEFFIT into five conceptual areas of functionality. These are

Generation of input files: The input structures to these programs are rather complicated and offer many options for the user. This is particularly true for FEFFIT, which uses a highly abstracted metalanguage for constraining parameters in a fitting model. Much of the functionality of @ease{} is dedicated to the generation and manipulation of the text of the various input files. The creation of input files is the most difficult part of using these programs. Thus I was motivated to use Emacs as the application/program interface. Along with good integration of system level features such as file handling and process handling, Emacs possesses extremely powerful text manipulation capabilities and a flexible keyboard and mouse based user model.
Program execution: @ease{} uses the Emacs system interface to execute the programs and to display their run-time messages. Although each of the programs requires that input files have filenames specific to the program (i.e. FEFF requires that its input file be called `feff.inp'), @ease{} allows you to use input files with arbitrary names. It uses a command wrapper to temporarily rename input files to the name expected by the executed program.
Organization of graphical output: @ease{} uses GNUPLOT to display data. Scripts for running GNUPLOT are generated automatically from the contents of the input files and may be saved for future use. Many display options exist for FEFFIT for plotting results in different spaces and for plotting the contributions from individual scattering paths.
Organization of textual output: Analysis of data is performed to obtain answers to physical questions. Pretty pictures are very important, but often a number is the bottom line. @ease{} has several features for organizing the textual output (such as the contents of log files) of the programs into useful formats.
Error handling and recovery from mistakes: Any program that can be used can be misused. @ease{} has features for examining the contents of input files for errors or inconsistencies. It also allows the user to examine the run-time and saved-file output of the programs.

@ease{} is an ongoing project. I hope that, in its present form, it will help you analyze your data. For some hints of what @ease{} might do in the future, take a peek at section Future work. If you have any questions, comments, complaints, or suggestions, please contact me. There is a bug report function built into @ease{} which sends me email using the Emacs mailer. It is invoked by C-c C-b b of from the Input - miscellaneous menu. Use that function or any of my contact information shown on the second page of this document.

Go to the first, previous, next, last section, table of contents.