diffpy.pdffit2 1.1a1

PDFfit2 - real space structure refinement program.

diffpy.pdffit2 - real space structure refinement to atomic PDF

The diffpy.pdffit2 package enables calculation and refinement of atomic Pair Distribution Function (PDF) from crystal structure model. It is used as a computational engine by PDFgui. All refinements possible in PDFgui can be done with diffpy.pdffit2, it is a lower level library and requires fair Python knowledge. The package includes a pdffit2 command-line application, which tries to mimic the old PDFFIT program. The pdffit2 program launches Python interactive session with several libraries and functions preloaded for convenience. The pdffit2 program is suitable for interactive use, however refinement scripts should be rather written as normal Python; this is more reliable and needs only few extra lines of code.

To learn more about diffpy.pdffit2 library, see the examples directory included in this distribution or the API documentation at

http://docs.danse.us/diffraction/diffpy.pdffit2

REQUIREMENTS

diffpy.pdffit2 requires Python2.5 and the following external software:

setuptools – software distribution tools for Python python-dev – header files for interfacing Python with C GSL – GNU Scientific Library for C g++ – GNU C++ compiler

On Ubuntu Linux the required software can be easily installed using the system package manager:

sudo aptitude install

python-setuptools python-dev libgsl0-dev g++

For other Linux distributions use their respective package manager; note the packages may have slightly different names. diffpy.pdffit2 should work on other Unix-like operating systems and on Mac as well. Please, search the web for instructions how to install external dependencies on your particular system.

INSTALLATION

Once the requirements are satisfied, diffpy.pdffit2 can be installed with

python setup.py install

This installs the library and the pdffit2 program to the default system directories. See the usage info “./setup.py install –help” for options to install under different locations. Note that installation to non-standard directories you may require adjustment to the PATH and PYTHONPATH environment variables.

The Python setuptools library provides “easy_install” script, which can be used to update diffpy.pdffit2 installation or even to perform a new install without explicit need to download and unzip the code:

easy_install -U diffpy.pdffit2

This checks the package repository at http://www.diffpy.org/packages/ for any newer releases of diffpy.pdffit2 and if present, it updates the installation. The easy_install can be also used to get in sync with the latest development sources in the subversion repository:

easy_install -U

svn://[e-mail]/diffraction/diffraction/diffpy.pdffit2/trunk

CONTACTS

For more information on diffpy.pdffit2 please visit the project web-page:

http://www.diffpy.org/

or email Prof. Simon Billinge at [e-mail]