EDM: Electron Direct Methods, Version 3.0

General Information Features Documentation Listserver Download Information FAQ Installation Limitations and Bugs NCEMSS Update Information and News Code Structure Online CVS

General Information

EDM is a set of programs intended to combine various aspects of image processing and manipulation of high resolution images and diffraction patterns as well as direct methods. The intent is to make available to the general user a relatively simple user-interface mouse driven version of what has been to date research oriented code. The code is Public Domain under the standard GNU license, which means that it is free to use or modify for non-commercial purposes.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

Because this program is licensed free of charge, there is no warranty for the program, to the extent permitted by applicable law. Except when otherwise stated in writing the copyright holders and/or other parties provide the program "as is" without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the program is with you. Should the program prove defective, you assume the cost of all necessary servicing, repair or correction.

Features

The full functionality of the software is relatively large, and includes:

1. A user friendly mouse-driven interface.
2. Crystallographic operations (e.g. symmetry averaging) on HREM images with good numerical
   accuracy (ppm in many cases).
3. A number of image processing options, including Wiener-filtering, masked/windowed Fourier Transforms and a Hanning Window Fourier Transform.
4. Accurate cross-correlation based methods of measuring spot diffraction intensities and user-friendly symmetry averaging with or without Friedel symmetry. (less accurate background subtraction methods are also included).
5. Accurate methods of extracting phases from HREM images.
6. An improved version of the direct methods code fs98 to solve structures, which can also be
   used with other types of data (e.g. surface X-ray diffraction) as well as TED intensity data. This uses a feasible set approach with a sharing protected genetic algorithm search and a Kullback–Liebler metric.
7. Code to perform structure completion (i.e. find where the atoms are) based upon kinematical models. 
8. HRTEM Image Simulation. The multislice code NCEMSS (National Center for Electron Microscopy Simulation Software) which is a separate package is installed by default for quantitative analysis of HREM images.
9. Code to calculate CBED patterns (beta)

Listserver

A listserver has been established to facilitate use, which can be used to ask (or answer) questions such as "How do I do XYZ" as well as general information. You can subscribe to the EDM Listerver by sending an email message to listserv@listserv.it.northwestern.edu with

    SUBSCRIBE EDM Firstname Lastname

in the body of the message.

Download Information

The most current version of the code is 3.0 which is currently only available by anonymous cvs (see below) or as a tar file as edm-3.0.tar.gz (11Mb), A windows executable will be available shortly edm-2.0.exe (18Mb) is also available. Beware that there are some issues with Visa which have not been fully resolved as yet.

The source code can be compiled using the standard configure/make structure. Please see BUGS, CHANGES and INSTALL for additional information. Note that the BUGS report in this file is more current than what is in the documentation. Full documentation (as full as is currently available) can be found here.

The Windows version is a self-extracting installer (built using NSIS) which will do a standard install. We have tested that they work on a range of versions (95, 98, ME, 2000, XP), but if you have a slow (e.g. 100MHz) computer with limited RAM (e.g. 64M) you might encounter the famous blue screen -- we are not sure. Please note that the code is designed for unix, so is not optimized for Windows but does run quite fast.

The best method is to download the latest EDM via anonymous cvs:

    cvs -d:pserver:anonymous@129.105.122.84:/home/cvsroot checkout edm

You can also directly access the cvs on the web at http://www.josephsmith.northwestern.edu/cgi-bin/edmcvs.cgi/