The Cryst package, previously known as CrystGAP, provides functions for the computation with affine crystallographic groups, in particular space groups. For the definition of the standard crystallographic notions we refer to the International Tables [Hah95], in particular the chapter by Wondratschek [Won95], and to the introductory chapter in [BBN+78]. The principal algorithms used in this package are described in [GEN97].
The present version for GAP 4 has been considerably reworked from an earlier version for GAP 3.4.4. Most of the porting to GAP 4 has been done by Franz Gähler. Besides affine crystallographic groups acting from the right, also affine crystallographic groups acting from the left are now fully supported. Many algorithms have been added, extended, or improved in other ways.
Our warmest thanks go to Max Neunhöffer, whose extensive testing of the GAP 4 version of Cryst in connection with XGAP uncovered several bugs and led to many performance improvements.
Cryst is implemented in the GAP 4 language, and runs on any system supporting GAP 4. However, certain commands may require that other GAP packages such as CaratInterface or XGAP are installed. In particular, the routines in Section 2.9 are likely to require CaratInterface, and the function WyckoffGraph (see WyckoffGraph (2.8-9)) requires XGAP. Both CaratInterface and XGAP may be available only under Unix.
The Cryst package is loaded with the command
gap> LoadPackage( "cryst" ); true
For bug reports, suggestions and comments please use the issue tracker on GitHub:
https://github.com/gap-packages/Cryst/issues/
generated by GAPDoc2HTML