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[ccp4bb]: New release of the Computational Crystallography Toolbox

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                New release of the

      Computational Crystallography Toolbox



The major addition is a general algorithm for the determination of the
space group type given symmetry operations (SgOps::getSpaceGroupType).
Associated with this are new algorithms for generating space group
symbols. The new features are used by the sgtbx_server.py script in the
examples/python directory. This script is also installed at:


This web resource is helpful to determine the type of the new space
group if some kind of additional symmetry is found, e.g. with the
program MISSYM, or to explore the implications of pseudo-translational
NCS for a protein crystal. For example, see:
In the sgtbx web form enter:
    Space group symbol: C2
    Additional symmetry operations:
    x+0.5, y, z
    x+0.25, y+0.25, z
    Space group number: 5
    Conventional Hermann-Mauguin symbol: C 1 2 1
    Change-of-basis matrix: 2*x,2*y,z
                   Inverse: 1/2*x,1/2*y,z
This is, in this particular example the space group type does not
change, but additional translations lead to a new unit cell with
the a and b parameters divided by 2.

General Information:

This Open Source package is a collection of fundamental
procedures for Computational Crystallography and currently
includes a unit cell toolbox (uctbx), a space group toolbox
(sgtbx) and an element toolbox (eltbx) for the handling of
scattering factors and other element properties.

The cctbx package is organized as a set of ANSI C++ classes
with Python bindings. Python is modern object-oriented
scripting language with a clear and elegant syntax. The
cctbx is therefore useful for crystallographers with a
variety of interests. The Python interface will enable
crystallographers who are less software oriented to use the
algorithms implemented in the cctbx. The Python interface
could also be useful in teaching crystallography.

The fastest way of getting started with the cctbx Python
interface is to use the pre-compiled Python modules for
Windows. The cctbx package also includes a highly automated
cross-platform build system with support for various
flavors of Unix and Windows 98 or higher.

The Computational Crystallography Toolbox is designed with
an open and flexible architecture to promote extendability
and easy incorporation into other software environments.
The use of both C++ and Python combines the computational
efficiency of a strongly typed compiled language with the
flexibility of a dynamically typed scripting language in a
strikingly uniform and very maintainable way.

Use of the Python bindings is highly recommended, but
optional. The Computational Crystallography Toolbox can
also be used purely as a C++ class library.

The current version of the cctbx was written by members of
the Computational Crystallography Initiative (CCI,
http://cci.lbl.gov/) at the Lawrence Berkeley National
Laboratory (http://www.lbl.gov/).

Project home page: http://cctbx.sourceforge.net/

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