----------------------------------------------------- New release of the Computational Crystallography Toolbox http://cctbx.sourceforge.net/ ----------------------------------------------------- Changes: 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: http://cci.lbl.gov/sgtbx/ 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: http://www.cryst.bbk.ac.uk/~ubcg09j/ccp4arc/bb2000/msg01093.html 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 Result: 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/