Changelog of the Package Cryst

Version 4.1.18

• Fixed trivial changes in output of a manual example and several test examples.

Version 4.1.17

• Bug in ConjugatorSpaceGroups fixed.

Version 4.1.16

• Bug in ImagesRepresentative for isomorphism to PcpGroup fixed.
• Bug in kernel of PointHomomorphism for left-acting group fixed.
• Bugs in Centralizer and CanonicalRightCosetElement fixed.
• Test files with better code coverage.

Version 4.1.15

• PackageInfo record corrected.

Version 4.1.14

• Corrected incompatible standardizations of affine subspaces.
• Added various testfiles.

Version 4.1.13

• Fixed a bug in ImagesRepresentative for IsFromAffineCrystGroupToPcpGroup.

Version 4.1.12

• Fixed a bug in RepresentativeAction for AffineCrystGroups.

Version 4.1.11

• Fixed a bug in the conjugation of left-acting AffineCrystGroups.
• Changed outdated RequirePackage in manual.

Version 4.1.10

• Fixed file permissions.

Version 4.1.9

• Minor Update

Version 4.1.8

• Bugfix in AffineNormalizer

Version 4.1.7

• Adapted to GAP 4.5

Version 4.1.6

• TranslationBasis for trivial point group fixed.
• Bug in ImagesRepresentative for IsomorphismFpGroup of an AffineCrystGroupOnLeft fixed.
• Multiplication with empty matrix in WyckoffPositions fixed.
• Membership test in AffineCrystGroups improved.

Version 4.1.5

• Incomplete translation basis fixed.

Version 4.1.4

• Two instances of multiplying an empty list with a matrix fixed

Version 4.1.3

• Mutability problem fixed

Version 4.1.2

• File manual.toc added

Version 4.1.1

• Online help should now work for all functions.
• Fixed several manual examples changed output or wrong input.
• Avoided some multiplications of an empty list with a matrix.
• Support for new package loading mechanism in GAP 4.4

Version 4.1

• Name change from CrystGAP (or CrystGap) to just Cryst. This avoids confusion, as even CrystGAP was always loaded as "cryst".
• A second algorithm for the computation of Wyckoff positions (due to Ad Thiers) has been implemented. It avoids the computation of a subgroup lattice, and is faster in small dimensions. It is used by default for dimensions <= 4. The two available algorithms can be called directly using the functions
  
  WyPosAT( S );  # algorithm due to Ad Thiers
  WyPosSGL( S ); # algorithm using the subgroup lattice
  
  These functions are still undocumented.
• A bug in WyckoffGraph was fixed. The labels of the lines in the graph were not what was intended, and the manual was even selfcontradictory in this respect. This required code for intersections of affine subspace lattices, and a better subset test for affine subspace lattices. These are still undocumented.
• The function ConjugatorSpaceGroups is now documented.
• Cryst now tries to load the package polycyclic, and then installs methods for IsomorphismPcpGroup for PointGroups and AffineCrystGroups.
• A method for ImagesRepresentative for an IsomorphismFpGroup of an AffineCrystGroup has been added, so that the resulting isomorphism can now really be used.
• Switch to the new attribute MappingGeneratorsImages. Compatibility with GAP 4.2 and GAP 4.1 is maintained.
• A bug in Normalizer for two AffineCrystGroupsOnLeft was fixed; it returned an AffineCrystGroupOnRight.
• The number of generators returned by Normalizer for two AffineCrystGroups was reduced.
• A bug in ConjugacyClassesMaximalSubgroups for space groups was fixed; their size was set to a wrong value in certain cases.
• A mutability bug in AffineNormalizer was fixed.

Version 4.0

• Initial Release for GAP 4