[GAP Forum] Release Announcement: GAP 4.4
Alexander Hulpke
hulpke at math.colostate.edu
Thu Apr 15 20:49:35 BST 2004
Dear Gap-Forum,
GAP 4.4 is available! It contains a variety of new features, improved
algorithms and new programming tools. A detailed outline is included
below.
We recommend all GAP 4 users to upgrade to GAP 4.4 and we wish you fun
and success in using GAP.
You can download the new version of GAP from
http://www.gap-system.org
The GAP group
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New Mathematical Features
-------------------------
* New Algorithms and Functions in GAP
- Groebner Bases:
Buchberger's algorithm to compute Groebner Bases has been implemented
in GAP. (By A. Hulpke)
For large scale Groebner Basis computations there also is an interface
to the Singular system available in the 'Singular' Package.
(By M. Costantini and W. de Graaf)
- Algebraic Field Extension:
New methods for factorizing polynomials over algebraic extensions of
the rationals have been implemented in GAP. (By A. Hulpke)
For more functionality to compute with algebraic number fields there
is an interface to the Kant system available in the 'Alnuth' Package.
(By B. Assmann and B. Eick)
- Galois Groups:
A method for computing the Galois group of a rational polynomial has
been implemented in GAP. (By A. Hulpke)
- Finite Groups:
A new operation and a new method to compute the minimal normal subgroups
of a finite group and a method to determine the socle of a finite group
has been installed. (By B. Hoefling)
- Permutation Groups:
A fast method for recognizing whether a permutation group is symmetric
or alternating in its natural representation is available now.
(By A. Seress)
- Brauer Tables:
The algorithm for 'BrauerCharacterValue' has been extended to the case
where the splitting field is not supported in GAP. (By T. Breuer)
Brauer tables of direct products can now be constructed from the
known Brauer tables of the direct factors. (By T. Breuer)
- Vector spaces:
Basic support for vector spaces of rational functions and of uea
elements is available now in GAP. (By T. Breuer and W. de Graaf)
- Integer matrices:
Various new functions for computations with integer matrices are
available, such as methods for computing normal forms of integer
matrices as well as nullspaces or solutions systems of equations.
(By W. Nickel and F. Gaehler)
- Meataxe:
It is now possible to compute invariant forms and orthogonal signs of
modules. (By D. Holt and J. Thackray)
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* New Packages for GAP
The following new Packages have been accepted.
- LAGUNA: Computing with Lie Algebras and Units of Group Algebras.
By V. Bovdi, A. Konovalov, R. Rossmanith, C. Schneider.
- NQ: The ANU Nilpotent Quotient Algorithm.
By W. Nickel.
- KBMAG: Knuth-Bendix for Monoids and Groups.
By D. Holt.
- QuaGroup: Computing with Quantized Enveloping Algebras.
By W. de Graaf.
- AlNuTh: Algebraic Number Theory and an Interface to the Kant System.
By B. Assmann and B. Eick
- Polycyclic: Computation with Polycyclic Groups.
By B. Eick and W. Nickel
- Sonata: Construction and analysis of finite nearrings.
By E. Aichinger, F. Binder, J. Ecker, P. Mayr, C. Noebauer
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* Performance Enhancements
- Character Theory:
The computation of irreducible representations and irreducible
characters using the Baum-Clausen algorithm and the implementation of
the Dixon-Schneider algorithm have been speeded up. The algorithm for
'PossibleClassFusions' has been changed: the efficiency has been
improved and a new criterion is used. The algorithm for
'PossibleFusionsCharTableTom' has been speeded up. The method for
'PrimeBlocks' has been improved following a suggestion of H. Pahlings.
- Symmetric Groups
New improved methods for normalizer and subgroup conjugation in Sn have
been installed and new improved methods for IsNaturalSn/An have been
implemented. These improve the available methods when groups of large
degrees are given.
- Permutation Groups:
The partition split method used in the permutation backtrack is now
in the kernel. Transversal computations in large permutation groups
are improved. The decomposition of a permutation as a word in the
generators now produces substantially shorter words: for example, the
words have lengths about 100 for the Rubics Cube group.
- Matrix Groups:
The membership test in SP and SU has been improved using the invariant
forms underlying these groups.
- Finite groups:
An improvement for the cyclic extension method has been implemented.
- Matrices:
A better method for MinimalPolynomial for finite field matrices has been
implemented.
- Polynomials:
The display has changed and the arithmetic of multivariate polynomials
has been improved.
- LogMod:
Uses now Pollard's rho method combined with the Pohlig/Hellmann approach.
(By Sean Gage)
- Lists:
Various functions for sets and lists have been improved following
suggestions of L. Teirlinck. These include: Sort, Sortex, SortParallel,
SortingPerm, NrArrangements.
- Finite Dimensional Algebras:
The methods for 'StructureConstantsTable' and 'GapInputSCTable' have
been improved in the case of a known (anti-) symmetry following a
suggestion of M. Costantini.
Unless otherwise stated, the improvements listed in this Section have been
implemented by T. Breuer and A. Hulpke.
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* Technical changes in GAP and new programming tools
- IsSimple: Returns false now for the trivial group.
- PrimeBlocks: The output format has changed.
- Division Rings: These are implemented as 'IsRingWithOne' now.
- DirectSumOfAlgebras: Pth power maps are compatible with the input now.
- EnumeratorByFunctions: A new tool to create enumerators.
- IteratorByFunctions: A new tool to create iterators.
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* Bug Fixes
It remains to mention that GAP 4.4 includes fixes for all bugs which
had been reported before the deadline for the release.
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New Programming and User Features
---------------------------------
- Workspaces: The 2GB limit has been removed and version numbers have
been introduced. (By S. Linton and B. Hoefling)
- Types: The limit on the total number of types created in a session
has been removed. (By S. Linton)
- Packages: There is a new mechanism for loading packages available.
Packages need a file PackageInfo.g now. (By T. Breuer and
F. Luebeck)
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Upwards Compatibility
---------------------
The mechanism for the loading of Packages has changed. Packages require
a file PackageInfo.g now. These new PackageInfo.g files are available
for all accepted and deposited Packages within GAP 4.4.
Apart from the Package loading, there are only some other very minor
changes (e.g. the trivial group is not a simple group in GAP any longer)
which are not compatible with GAP 4.3.
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License and Installing GAP 4.4
------------------------------
GAP is free software which is distributed under the GNU general public
licence. You can get GAP 4.4 from
- http://www.gap-system.org
- ftp://ftp.gap-system.org in the directory pub/gap/gap4.
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Acknowledgements
---------------
* Personal Support
The members of the GAP development team are working on GAP as a part of
their research or in their free time. The GAP development team has members
all over the world and thus GAP can be considered as a world wide joint
research project. A list of the members of the GAP development team can
be found in the Tutorial manual of GAP.
A significant part of the functionality of GAP is available in the GAP
packages. These are independently developed packages of code with their
own author lists. A detailed list of the available GAP packages can be
found on the GAP web pages.
Finally, there is a long list of collaborateurs and users of GAP. The
feedback and constructive critism of these people has helped to fix bugs
and to improve the system. Many thanks are due to all these people.
* Financial Support
We acknowledge with gratitude the support of the development of GAP
provided by a variety of funding bodies. Details can be found on the GAP
web pages.
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Bugfixes
--------
If you have followed the releases of GAP over the last years you might
have noted that a first bugfix typically comes early after a release. This
is despite of extensive testing, but unfortunately reflects the limited
size of the developer group compared to the user community. We simply
might not have thought of doing certain things. If the experience of
previous releases holds, we therfore will have a first update within the
next two or three weeks. You might want to plan accordingly.
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