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\Chapter{Installation}

This package must be installed in the `pkg' subdirectory of any of
the {\GAP} 4 root directories. We assume here that this is `/gap4/pkg'.

\begintt
cd /gap4/pkg
unzoo -x carat-2.1.zoo
\endtt

This creates a subdirectory `carat', the home directory of the present
interface package. {\CARAT} itself can be installed anywhere on your 
system. You only have to make sure {\GAP} finds the {\CARAT} binaries, 
by making a symbolic link from the `bin' subdirectory in `pkg/carat' to 
the `bin' subdirectory of {\CARAT} itself. In our example, we install 
{\CARAT} in `/gap4/pkg/carat' (the {\CARAT} tar file should already be 
there):

\begintt
cd /gap4/pkg/carat
zcat carat-2.1b1.tgz || tar pxf -
ln -s carat-2.1b1/bin bin
cd carat-2.1b1
\endtt

This creates a subdirectory `carat-2.1b1', the {\CARAT} top level directory. 
You have to edit the Makefile in that directory. In particular, you have 
to set the variables TOPDIR (to `/gap4/pkg/carat/carat-2.1b1'), CC, and 
CFLAGS (to your favourite set of compiler options). Then do 

\begintt
make
\endtt

If you build for more than one architecture, make sure to do a 
'make clean' in between.

Like any other {\GAP} 4 package, {\CARAT} is then loaded in {\GAP} with

\beginexample
gap> LoadPackage("carat");
true
\endexample

This package, together with {\CARAT} itself, takes some 208Mb of disk space,
or more, depending on the system. Some 170Mb is taken by the catalog
of Q-classes if integer matrix groups up to dimension 6. If you want
to avoid unpacking this catalog, you can create empty subdirectories

\begintt
cd /gap4/pkg/carat/carat-2.1b1
mkdir tables
mkdir tables/qcatalog
\endtt

before making {\CARAT}. If you want to unpack the catalog later, just
remove the empty directory `tables/qcatalog', and do

\begintt
make Qcatalog
\endtt