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\Chapter{Introduction}
\index{caratinterface}
The package {
\CaratInterface} contains GAP interface routines to {
\CARAT},
a package of programs for the computation with crystallographic
groups. {
\CARAT} is implemented in C, and has been developed by
J.~Opgenorth, W.~Plesken, and T.~Schulz at Lehrstuhl~B f
\accent127ur
Mathematik, RWTH Aachen. The algorithms used by {
\CARAT} are described
in
\cite{OPS98}.
{
\CARAT} is to a large extent complementary to the {
\GAP} package
{
\Cryst}. In particular, it provides routines for the computation
of normalizers and conjugators of finite unimodular groups in $GL(n,Z)$,
and routines for the computation of Bravais groups, which are all
missing in {
\Cryst}. Furthermore, {
\CARAT} provides also a catalogue of
Bravais groups up to dimension 6. {
\Cryst} automatically loads {
\CARAT}
when it is available, and makes use of its functions where necessary.
The present package thereby extends the functionality of {
\Cryst}
considerably.
{
\CARAT} itself is NOT part of this package. However, for your convenience,
and in accordance with the {
\CARAT} license, a copy of {
\CARAT} is
included. It is this version with which the interface routines
have been tested. The most recent version of {
\CARAT} can be obtained at
its home page
\beginitems
&
\URL{
https://lbfm-rwth.github.io/carat}.
\enditems
The {
\GAP} interface routines to {
\CARAT} have been written by
\beginitems
&
Franz G
\accent127ahler\hfill\break
Fakult
\accent127at f
\accent127ur Mathematik
\hfill\break
Universit
\accent127at Bielefeld
\hfill\break
Postfach 10 01 31
\hfill\break
D-33501 Bielefeld
\hfill\break
\Mailto{gaehler@math.uni-bielefeld.de}
\enditems
For bug reports, suggestions and comments regarding the interface routines,
please use the issue tracker on GitHub:
\beginitems
&
\URL{
https://github.com/gap-packages/CaratInterface/issues/}
\enditems
Bug reports regarding {
\CARAT} itself should be reported in the
{
\CARAT} issue tracker on GitHub:
\beginitems
&
\URL{
https://github.com/lbfm-rwth/carat/issues/}
\enditems
